Main groups of different biodegradable plastics.
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This Article is part of Environmental Engineering & Clean Technologies Section
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Article Type: Review Paper
Date of acceptance: June 2025
Date of publication: July 2025
DoI: 10.5772/geet.20250011
copyright: ©2025 The Author(s), Licensee IntechOpen, License: CC BY 4.0
The growing environmental concerns regarding plastic pollution have driven research toward biodegradable plastics as a sustainable alternative to conventional petroleum-based polymers. Biodegradable plastics, derived from renewable sources such as starch, polylactic acid, and polyhydroxyalkanoates, offer a promising solution to mitigate plastic waste accumulation. This review explores the current scenario of biodegradable plastics, emphasizing their environmental significance in reducing landfill burden and marine pollution. Various production methods, including microbial fermentation, chemical synthesis, and biopolymer blending, are discussed to highlight advancements in sustainable manufacturing processes. The physicochemical and mechanical properties of biodegradable plastics, including tensile strength, degradation rate, and thermal stability, are analysed to assess their viability across industries. Furthermore, their applications span packaging, agriculture, biomedical fields, and consumer goods, demonstrating their versatility of use. However, cost competitiveness remains a significant challenge, as biodegradable plastics often have higher production costs than conventional plastics, limiting large-scale adoption. Strategies such as improved bioprocessing techniques, policy interventions, and circular economy approaches are essential for enhancing economic feasibility. This review underscores the need for continued innovation and policy support to drive the widespread adoption of biodegradable plastics, ultimately contributing to a sustainable and environmentally responsible future.
biodegradable plastics
environmental impact
plastic waste reduction
renewable resources
sustainable polymers
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The disposal of plastic waste has emerged as a critical environmental challenge, driven by the extensive production and pervasive use of synthetic polymers in modern society. The accumulation of non-biodegradable plastics, such as polyethylene, polypropylene, and polyvinyl chloride, significantly contributes to environmental pollution and global warming, particularly through the emission of carbon dioxide during their incineration. In response to this pressing issue, the development of biodegradable polymers has gained considerable attention as a sustainable alternative to conventional plastics. These eco-friendly materials present a promising strategy for mitigating plastic waste by decreasing dependence on non-biodegradable polymers and facilitating recycling or reuse. As a result, research and development efforts focused on biodegradable materials have significantly intensified, driven by the increasing concerns regarding plastic pollution and its associated environmental impact [1].
Biodegradable polymers are engineered materials designed to perform specific functions over a defined time span before undergoing degradation into non-toxic byproducts through biological (microbial degradation, enzymatic degradation) or physicochemical processes (hydrolysis, environmental triggers such as temperature, humidity, pH, light (especially UV), and oxygen availability). These polymers are derived from a wide range of renewable feedstocks and waste materials, including agricultural residues, food waste, animal byproducts, starch, and cellulose [2–4]. Among these, plant-based bioplastics are usually cost-effective and industrially scalable than those produced through microbial fermentation, encouraging a shift toward renewable-based production systems. The adoption of biodegradable polymers presents several environmental advantages, including reduced reliance on petrochemical-derived plastics, regeneration of raw materials, and mitigation of greenhouse gas emissions, particularly carbon dioxide, thereby contributing to efforts against global warming [5]. The degradation of these materials is predominantly mediated by microorganisms such as bacteria (Pseudomonas putida, Bacillus subtilis) and fungi (Aspergillus niger, Penicillium funiculosum) which enzymatically cleave the polymer chains into simple end products such as carbon dioxide (CO2), water (H2O), and methane (CH4). The rate and extent of biodegradation are influenced by various factors, including the polymer’s molecular structure, composition, morphology, molecular weight, and prior exposure to chemical or radiation treatments. Various studies have shown that environmental and physicochemical factors significantly influence the rate of polyethylene biodegradation. Using the thermophilic bacterium Brevibacillus borstelensis, researchers observed enhanced degradation at an optimal temperature of 50 °C, where increased microbial activity and polymer flexibility facilitated breakdown [2]. Pre-treatment of polyethylene with UV irradiation induced photo-oxidation, generation of carbonyl groups that increased surface hydrophilicity and microbial accessibility. This modification significantly improved enzymatic degradation, as confirmed by FTIR analysis capturing the changes in functional groups and increased polymer erosion. The combined effect of thermal conditions and UV pre-treatment led to a notably higher biodegradation rate compared to untreated controls, emphasizing that controlled environmental modifications can accelerate polyethylene degradation and support effective bioremediation strategies [6, 7].
Bacillus megaterium was employed to synthesize PHA (polyhydroxyalkenate) from sugarcane bagasse hydrolysate. The resulting biopolymer underwent biodegradation tests under composting conditions, where more than 60% of its mass degraded within 60 days. This study underscores the potential of converting lignocellulosic biomass into high- value biodegradable plastics and their effective breakdown in natural environments, highlighting the practical applicability of biopolymer technologies in sustainable waste management [8].
There are two principal motivations for the development and utilization of polymers derived from renewable resources. The first is to mitigate environmental issues associated with the accumulation of plastic waste and the intensification of global warming, the latter being further aggravated by carbon dioxide emissions resulting from plastic incineration. The second is to address the progressive depletion of non-renewable petroleum-based resources. While the biodegradable plastics sector demonstrates considerable promise, its sustainable advancement necessitates a thorough evaluation of end-of-life treatment strategies. Furthermore, effective global integration with organic waste management infrastructure is imperative, especially in light of the ongoing expansion of source- separated bio waste collection systems [9].
Biodegradable plastics present a sustainable end-of-life option as they can undergo biological decomposition through processes such as composting or anaerobic digestion. The compostability of these materials has been extensively studied and is globally acknowledged under home and industrial composting conditions [10]. Under aerobic conditions, these plastics are broken down into carbon dioxide, water, and biomass. Microbial degradation of these materials in anaerobic environments leads to the production of biogas, a mixture primarily composed of carbon dioxide and methane. This biogas can be harnessed as a renewable energy source for heat and electricity generation, thereby enhancing the environmental and economic value of the anaerobic digestion process [11].
The development of alternative and specialized waste management strategies presents a critical challenge in the integration of biopolymers within the circular economy framework. Biodegradable polymers are categorized as bio-based or synthetic based on their origin and are increasingly being adopted as substitutes for conventional, non-biodegradable plastics in diverse applications such as packaging materials and single-use plastic bags, thereby addressing the growing issue of environmental waste accumulation. In the biomedical field, biodegradable polymers are of particular importance, serving pivotal roles in advanced applications including soft tissue engineering and gene delivery systems. These materials significantly contribute to the progress of medical therapeutics and regenerative medicine by offering biocompatibility, controlled degradation, and functional versatility [12].
This review critically examines the recent advances in biodegradable plastics, emphasizing their ecological significance and prospective role in fostering environmental sustainability. It also provides a comprehensive analysis of their synthesis pathways, degradation mechanisms, functional applications, and the regulatory frameworks that govern their use. By integrating recent findings and technological progress, this study aims to elucidate the potential of biodegradable plastics as viable alternatives to conventional polymers, thereby contributing to the mitigation of plastic pollution and the realization of a circular economy.
Unlike conventional plastics, which can persist in the environment for centuries, biodegradable plastics offer a more sustainable alternative for reducing long-term pollution. Biodegradable plastics are designed to break down into natural substances, such as water, carbon dioxide, and biomass, through the action of microorganisms. They are derived from renewable resources like plant-based materials or from petrochemicals with additives that enhance their breakdown. Biodegradable plastics present an eco-friendly solution; their degradation often requires specific conditions, such as industrial composting facilities [13].
Expanding their use and improving their breakdown in natural environments remains a critical focus in addressing plastic waste challenges. Biodegradable plastics can be categorized into several main groups: starch-based plastics, polylactic acid (PLA), polyhydroxyalkanoates (PHA), and biodegradable polyesters such as polybutylene adipate terephthalate (PBAT) and polybutylene succinate (PBS). These materials degrade through microbial action, making them eco-friendly alternatives to conventional plastics, with applications in packaging, agriculture, and medical fields due to their varied properties and origins.
Bio-based plastics are made partially or fully from renewable biological sources, such as plant- based materials like corn, sugarcane, or algae. They are considered as sustainable alternatives to traditional plastics, which are petroleum-based. Bio-based plastics are either biodegradable (PLA, PHA, PBS) or non-biodegradable (polytrimethylene terephthalate (PTT), Polyamide 11), depending on their chemical structure. Bio-based plastics typically have a lower carbon footprint because they sequester carbon dioxide during the plant growth phase, helping mitigate greenhouse gas emissions [14].
Bio-based plastic is compostable under specific conditions (temperature, pH, microbial activity, oxygen availability) reducing long-term pollution in natural environments. Bio-based plastics are widely used in various sectors. In packaging, they are applied in food containers, bottles, and shopping bags. In agriculture, bio-based films and biodegradable pots are used to reduce plastic waste in farming. Textiles benefit from bio-based fibers used in clothing and upholstery, while automotive parts like interior trims and cushions are now incorporating bio-based materials. Additionally, bio-based plastics are used in consumer goods, such as electronics casings and sports equipment, and medical device including surgical sutures and drug delivery systems as depicted in Figure 1 [15]. Figure 1 illustrates the anticipated global distribution of bio-based plastic demand in 2025 across various sectors. Packaging represents the dominant application at 48%, indicating its crucial role in sustainable containment. Building and construction account for 7%, while consumer goods constitute 13%. Automotive and transportation utilize 12%, followed by textiles at 11% and agriculture at 8%. The remaining 1% encompasses other diverse applications [16].
Uses of bio-based plastic.
Bio-based plastics are of various types, based on the source from which it has been derived. The common types used presently are shown in Figure 2 and described as follows:
Different types of bio-based plastics.
Cellulose-based bioplastics are derived from cellulose, a linear polysaccharide consisting of 𝛽-(1 → 4)-linked D-glucose units, making it the most abundant biopolymer on Earth [17]. The transformation of cellulose into a plastic material requires chemical modifications to overcome its rigid, crystalline structure and insolubility in common solvents. Key processes include acetylation (producing cellulose acetate), esterification, or the formation of cellulose derivatives such as cellulose ethers and esters, which introduce thermoplasticity by disrupting hydrogen bonds and decreasing crystallinity. Few studies have explored cellulose modification via acetylation, esterification, and etherification, emphasizing structural alterations that reduce hydrogen bonding and crystallinity, thereby enhancing solubility and imparting thermoplastic properties for sustainable polymer applications in industrial and biomedical fields [18]. Importantly, cellulose-based bioplastics exhibit good mechanical strength, thermal stability, and oxygen barrier properties, which are critical for applications in packaging and biomedical fields. Their environmental benefits are further amplified by their ability to degrade under composting conditions, unlike traditional plastics, which persist in ecosystems for centuries. However, challenges such as the high cost of production, processing limitations, and achieving properties comparable to petrochemical plastics still need to be addressed for their widespread adoption [19].
Starch-based bioplastics are derived from starch, a naturally occurring polysaccharide composed primarily of amylose (linear chains of 𝛼-(1 → 4)-linked D-glucose) and amylopectin (branched chains with 𝛼-(1 → 6) linkages). The conversion of starch into bioplastics typically involves the disruption of its semi-crystalline structure via plasticizers such as glycerol or sorbitol, which lower its glass transition temperature and increase flexibility. During the process, heat and shear forces cause gelatinization of starch, breaking down intermolecular hydrogen bonds and transforming the starch granules into an amorphous, moldable material. Depending on the ratio of amylose to amylopectin and the type of plasticizer used, the mechanical properties of the resulting bioplastic can be tailored, with higher amylose content generally resulting in stronger, more rigid bioplastics due to increased hydrogen bonding. Few studies have examined the influence of amylose-to-amylopectin ratio on starch-based bioplastics. It has been demonstrated that higher amylose content enhances thermal stability and mechanical strength due to extensive hydrogen bonding and molecular alignment. This increases gelatinization temperature and results in bioplastics with improved rigidity and lower water permeability. These findings support tailoring starch formulations based on amylose levels to optimize bioplastic performance for specific applications [20]. Starch-based bioplastics find use in packaging, disposable products, and agricultural films, with ongoing research focusing on enhancing their water resistance and structural properties through cross-linking and the incorporation of nanoparticles, broadening their applicability as a sustainable alternative to petroleum-based plastics [21].
Protein-based bioplastics are derived from natural proteins such as soy protein, casein, whey, gluten, and zein, which possess unique structural properties due to their complex polypeptide chains made up of amino acids. These proteins can be transformed into bioplastics through various denaturation processes, including heat, pH adjustment, or enzymatic treatments, which disrupt the native protein structure, allowing intermolecular interactions like hydrogen bonding, hydrophobic interactions, and disulfide linkages to form a network. The plasticization of proteins often requires additives like glycerol or sorbitol to improve flexibility and reduce brittleness. Depending on the protein source and processing conditions, protein- based bioplastics exhibit a range of mechanical properties, from rigid, strong materials (e.g., soy protein) to more flexible films (e.g., gelatin-based bioplastics). The key advantages of protein-based bioplastics include their renewable origin, inherent biodegradability, and potential for functionalization due to the reactive side groups on amino acid residues, which enable chemical modifications to tailor properties like water resistance, mechanical strength, and thermal stability [22].
Aliphatic polyesters are a prominent class of biodegradable bioplastics, synthesized from monomers linked by ester bonds in a repeating sequence of aliphatic (non-aromatic) chains. These bioplastics, which include polymers like PLA, PHA, PBS and polycaprolactone are widely valued for their biodegradability, biocompatibility, and relatively low environmental impact. Their structure, dominated by ester linkages, allows them to undergo hydrolytic and enzymatic degradation, making them suitable for applications requiring biodegradation, such as packaging, agricultural films, and medical implants [23]. The mechanical and thermal properties of aliphatic polyesters vary depending on their specific chemical structure. PLA for instance, exhibits high stiffness and good transparency, but is brittle, requiring plasticization or blending with other polymers to enhance flexibility. PHA produced by microbial fermentation, has better mechanical properties and flexibility but is costlier to produce [24]. PBS and polycaprolactone on the other hand, offer greater flexibility and superior thermal stability but may degrade more slowly under certain environmental conditions. Aliphatic polyesters also possess tunable degradation rates, which can be adjusted by altering their chemical composition or copolymerizing with other monomers, allowing control over their lifespan in various applications [25].
PLA (polylactic acid) is a widely used bioplastic derived from renewable resources such as corn starch, sugarcane, or cassava, and is synthesized through the polymerization of lactic acid monomers. PLA is produced via two primary methods: direct condensation of lactic acid or ring-opening polymerization of lactide, a cyclic dimer of lactic acid, the latter being more commercially favoured due to better control over molecular weight and properties. PLA’s structure consists of repeating units of lactide, and its stereochemistry (D- and L- isomers) influences its crystallinity and mechanical properties. For instance, PLA with high L-content tends to be semi-crystalline, which enhances its strength and thermal resistance, whereas amorphous PLA is more transparent and flexible but has lower mechanical performance [26]. PLA exhibits several desirable properties, such as good tensile strength, transparency, and processability, making it suitable for applications in packaging, textiles, and biomedical devices like sutures and drug delivery systems. It is also compostable under industrial conditions, where high temperatures and microbial activity facilitate its degradation into CO2, water, and biomass. However, hydrolytic degradation of PLA is relatively slow in natural environments, particularly in marine or soil settings, where conditions including low ambient temperatures, limited moisture, and reduced microbial activity are suboptimal and less favourable for biodegradation. PLA requires elevated temperatures (above 50 °C) and sufficient humidity for effective hydrolysis, conditions typically found in industrial composting facilities. Additionally, natural environments lack the specific thermophilic microorganisms necessary to break down PLA efficiently. Factors like neutral pH and limited surface area exposure further hinder microbial colonization and water penetration, collectively resulting in the slower degradation of PLA outside controlled settings [27].
PHB (poly 3-hydroxybutyrate) is a biopolymer belonging to the PHA family, produced naturally by various microorganisms, such as Ralstonia eutropha, as an intracellular carbon and energy storage material under nutrient-limited conditions with excess carbon. Structurally, PHB is a semi-crystalline polymer composed of repeating 3-hydroxybutyrate monomers connected via ester linkages. Its biodegradable and biocompatible nature makes PHB highly attractive for environmental and biomedical applications, including packaging, agricultural films, and tissue engineering scaffolds. PHB is synthesized through microbial fermentation, where bacteria accumulate it in granules, which can be harvested and purified after fermentation. The microbial production process, while sustainable, is often limited by the high cost of substrates and processing compared to petroleum-derived plastics. PHB is often blended with other polymers, such as polyhydroxybutyrate-co-valerate or polycaprolactone (PCL) which introduce flexibility and toughness which are limited in pure PHB due to its brittleness and high crystallinity. Polyhydroxybutyrate-co-valerate, being a copolymer, lowers the melting point and enhances processability, making it more suitable for packaging and biomedical applications. PCL adds elasticity and improves impact resistance, expanding the use of PHB blends in areas like controlled drug delivery, biodegradable films, and agricultural mulch. These modifications make PHB-based materials more adaptable to diverse practical applications where durability and mechanical resilience are essential. Moreover, PHB production can be optimized by genetic engineering of microbial strains and metabolic pathways to increase yields and reduce costs [28].
PHA (Polyhydroxyalkanoates) are a family of biodegradable and biocompatible polyesters synthesized by various bacteria as intracellular carbon and energy storage compounds under nutrient-limited conditions with an excess of carbon. PHA is produced through microbial fermentation and consist of various hydroxyalkanoate monomers, resulting in a wide range of material properties. The most well-known PHA, PHB (poly (3-hydroxybutyrate) is highly crystalline and exhibits good tensile strength but suffers from brittleness. Other copolymers, like PHBV (poly 3-hydroxybutyrate-co-3-hydroxyvalerate), introduce greater flexibility and toughness, broadening the potential applications of PHA and the inclusion of 4-hydroxybutyrate (4HB) enhances elasticity, making the polymer suitable for medical applications like sutures. Similarly, monomers like 3-hydroxyhexanoate (3HHx) and 3-hydroxyoctanoate (3HO) produce medium-chain-length PHA with rubber-like flexibility and lower melting points, ideal for films and coatings. These structural variations tailor PHA for specific industrial and biomedical uses. PHBV is preferred over PHB or other PHA types; for instance, PHBV is used in controlled drug delivery systems. Due to its biodegradability and biocompatibility, PHBV is used to create polymer-based drug carriers that gradually release medications over time. This application is particularly beneficial in implantable devices, where PHBV’s controlled degradation ensures sustained therapeutic effects without the need for removal. PHA is synthesized by microbial strains, including Ralstonia eutropha and Pseudomonas species, using renewable feedstocks such as agricultural waste, sugars, or even waste oils, making their production more sustainable than petrochemical-derived plastics. The biodegradability of PHA is its most significant advantage, as they degrade fully in various environments, including marine, soil, and compost, through enzymatic hydrolysis and microbial activity, producing water and carbon dioxide [29]. PHA, including PHB and PHBV, degrade at different rates depending on environmental factors such as temperature, moisture, microbial activity, and oxygen availability. PHA degrades more slowly in soil than in industrial composting, with PHB taking 6–12 months and PHBV 1–2 years, influenced by soil conditions and microbial diversity. In marine environments, PHA degrades within 1–2 years, with PHBV generally degrading faster than PHB due to the presence of diverse marine microorganisms. In composting, PHA breaks down within 6–12 months under optimal conditions of high temperature and moisture. In freshwater, degradation can take 1–3 years, with microbial communities accelerating the process. Read et al. [30] determined the degradation of 150 𝜇m-thick extruded sheets of PHBV submerged in five different natural aquatic environments within the same watershed for nearly 51 weeks. The study aimed to determine and compare the lifetimes and degradation behaviors of PHBV in these environments. The findings provide valuable insights into the degradation rates and mechanisms of PHBV in various natural aquatic settings [30].
PA 11 (Polyamide 11) is a bio-based thermoplastic polymer synthesized from 11-aminoundecanoic acid, a monomer derived from castor oil, making it a fully renewable material. PA 11 belongs to the broader class of polyamides (nylons), but unlike petroleum- based polyamides such as nylon 6 or nylon 6, 6; its renewable feedstock significantly reduces its environmental impact. The polymerization of 11-aminoundecanoic acid forms long aliphatic chains with amide linkages, giving PA 11 its excellent combination of mechanical strength, flexibility, and chemical resistance. Its high degree of crystallinity, coupled with its relatively long methylene chain between the amide groups, imparts superior toughness and ductility compared to many other polyamides, alongside low water absorption, which enhances its dimensional stability in humid environments. PA 11 is prized for its thermal stability and good impact resistance, even at low temperatures, making it ideal for demanding applications such as automotive fuel lines, electrical cable sheathing, and high-performance sporting goods [31]. Studies have demonstrated the development of PA 11 nanocomposites reinforced with graphene nanoplatelets (GNPs) for flexible pipeline applications. Results have shown that incorporating 1.0 wt% GNPs into the PA 11 matrix significantly enhanced thermal stability, as evidenced by thermogravimetric analysis (TGA), and improved mechanical properties, including increased storage and loss moduli observed through dynamic mechanical analysis (DMA). Additionally, the nanocomposites exhibited greater hydrophobicity and resistance to hydrothermal aging at 85 °C, maintaining higher corrected inherent viscosity (CIV) values compared to neat PA 11. These findings suggest that low GNP loadings effectively bolster PA 11’s thermal and mechanical performance, making it suitable for demanding applications in the oil and gas industry [32].
Bio-polyethylene or renewable polythene is derived from ethanol, which converts to ethylene after a dehydration procedure. Ethanol can be obtained from sugar beet, corn, sugar cane and wheat grain. This plastic is non-biodegradable and has the same physical and chemical characteristics as synthetic polythene. It is used in flexible and rigid packaging, bags, closures and various other products. It emits comparatively less CO2 in its production as compared to petroleum-based polyethylene [33].
When cyclic carbonates and polyamides are condensed, it produces PHUs (polyhydroxy urethanes). It is used in making foams, sealants, adhesives, and coatings, insulation of refrigerator, mattress, car parts, paints, tires, shoe soles, wood panels, and sportswear and emerging applications of PHUs include their use in biomedical materials, coatings, adhesives, and elastomers. Recent trends highlight their potential in self-healing materials, 3D printing resins, and flexible electronics, driven by their tunable network structures and compatibility with bio-based monomers. Research continues to optimize their performance for high-value, eco-friendly applications [34].
Biodegradable plastics are emerging as sustainable alternatives to conventional plastics derived from petrochemicals. The production of biodegradable plastics utilizes a variety of renewable feedstocks that are derived from plant-based sources, microbial processes, and waste materials and these varieties. Feedstock sources of biodegradable plastic are shown in Figure 3. These feedstocks are renewable, bio-based, and are capable of undergoing biological degradation, which significantly reduces the environmental burden associated with plastic pollution. The feedstock categories are plant-based, waste/residue-based, microbial-based, and other renewables highlight diverse, sustainable sources driving bioplastic production through efficient, eco-friendly, and circular bioeconomy pathways. Presently, the production of biodegradable plastics are based on agricultural waste, specifically sugarcane bagasse and wheat straw, as feedstock. The lignocellulosic biomass was pretreated and subjected to microbial fermentation using Cupriavidus necator, a well-known PHA-producing bacterium. The study demonstrated efficient conversion of the biomass into PHA, achieving high yields under optimized conditions. Characterization of the resulting bioplastics revealed favorable mechanical and thermal properties suitable for packaging applications. This approach not only adds value to agricultural residues but also presents a sustainable and circular strategy for bioplastic production, reducing reliance on petrochemical sources [35]. The feedstocks are classified into several categories: plant-based feedstocks, waste and residue-based materials, microbial-based raw materials, and other renewable sources. Each category is summarized in Tables [32] , highlighting the key characteristics along with a flow chart depicting the production processes [36]. Feedstock sources of biodegradable plastic are shown in Figure 3.
Different Feedstocks sources of biodegradable plastics.
Starch is a natural polymer that serves as a primary raw material for biodegradable plastics. It is extracted from various crops such as maize (corn) (Zea mays), potato (Solanum tuberosum), wheat (Triticum aestivum), and cassava (Manihot esculenta) and few examples of plant based feedstocks of biodegradable plastic are shown in Table 1 and Table 2. Table 1 also elucidates that starch from crops like maize and cassava produces thermoplastic starch for food packaging, while sugar crops like sugarcane yield PLA for films. Other sources include vegetable oils for PHA, agricultural residues for cellulose acetate, and microalgae for biodegradable packaging. The polysaccharides, amylose and amylopectin present in starch contribute to its thermoplastic properties when subjected to plasticization processes. Maize starch is extensively used due to its availability and cost efficiency. It is chemically or enzymatically modified to produce TPS (thermoplastic starch), which serves as a key component for bioplastic applications. Starch-based bioplastics are also commonly blended with other biodegradable polymers, such as PLA, to improve mechanical and thermal properties. Potato and cassava are also viable sources of starch. They are used particularly in regions where they are produced abundantly, such as Europe and Southeast Asia. These starches are transformed into biopolymers that find applications in food packaging, disposable utensils, and agricultural films. The cost competitiveness of biodegradable plastics in comparison to conventional plastics is presented in Table 3 [37].
Bio-based bioplastics | Bio plastic-synthetic polymers | Oxo-degradable plastics | References |
---|---|---|---|
Produced partly or entirely with biologically sourced polymers. Not all are biodegradable | Derived from synthetic polymers | Conventional plastics with additives to break down faster | [6] |
Photo-Biodegradable plastics | Hydro-Biodegradable plastics | Compostable plastics | |
Reach to ultra-violet light, and it requires initial oxo-degradation | Made from plant sources and the degradation is initiated by hydrolysis | Not synonymous with biodegradable, the difference is the setting to break down and the materials | [6] |
Main groups of different biodegradable plastics.
Feedstock | Source crops | Biopolymer produced | Applications | References |
---|---|---|---|---|
Starch | Maize, potato, cassava | Thermoplastic starch | Food packaging, utensils | [19] |
Sugar crops | Sugarcane, sugar beet | Polylactic acid (PLA) | Packaging materials, films | [20] |
Vegetable oils | Soybean, palm, castor | Polyhydroxyalkanoates (PHA) | Biodegradable containers, coatings | [20] |
Agricultural residues | Rice husk, wheat straw | Cellulose acetate | Chemical pretreatment | [21] |
Food waste | Fruit peels, spent grain | Biodegradable films | Enzymatic hydrolysis | [20] |
Waste oils | Used cooking oil | PHA | Microbial fermentation | [21] |
Microalgae | Algal biomass | PHA | Biodegradable packaging | [22] |
Bacterial biomass | Cupriavidus necator | PHA | Medical implants, films | [23] |
Lignocellulosic biomass | Wood chips, miscanthus | PLA, PHA | Films, biocomposites | [20] |
Chitin | Crustacean shells | Chitosan | Antimicrobial films | [21] |
Examples of plant-based feedstocks for biodegradable plastics.
Category | Biodegradable plastics (e.g., PLA, PHA) | Conventional plastics (e.g., PE, PP) | Comments | References |
---|---|---|---|---|
Cost per ton | $2,000–$7,000 | $1,000–$2,000 | Bioplastics are significantly more expensive | [39] |
Raw material source | Renewable (e.g., corn, sugarcane, waste) | Fossil fuels (e.g., petroleum) | Bioplastics rely on agricultural crops or waste feedstocks | [39] |
Production process | Fermentation, advanced technology | Cracking, polymerization | Bioplastics require more complex, energy-intensive processes | [39] |
Market Share (2023) | 1% of global plastics | Majority of the global market | Conventional plastics dominate due to scale and infrastructure | [39] |
Price sensitivity | Lower sensitivity to oil price fluctuations | Highly sensitive to crude oil prices | Bioplastics’ costs are less tied to fossil fuel volatility | [39] |
Future cost trend | Expected to decrease with innovation and scaling | Stable, but fluctuates with oil prices | Bioplastics will become more competitive as technology improves | [39] |
Environmental impact | Lower (compostable, reduced emissions) | Higher (non-biodegradable, pollution) | Biodegradable plastics have environmental advantages | [39] |
Cost competitiveness of biodegradable plastic with conventional plastics.
Sugar crops, including sugarcane (Saccharum officinarum) and sugar beet (Beta vulgaris), are widely used for the production of lactic acid—a key monomer in the synthesis of PLA. Sugarcane is a preferred feedstock for lactic acid fermentation in tropical and subtropical regions, while sugar beet is cultivated in cooler climates. PLA is produced through the fermentation of sugars to lactic acid, followed by polymerization. Sugarcane-based PLA is popular in countries like Brazil, India, and Thailand, which have substantial sugarcane cultivation [38].
Vegetable oils, such as soybean (Glycine max), palm oil (Elaeis guineensis), and castor oil (Ricinus communis), serve as carbon feedstocks for microbial production of PHA, which are biodegradable polyesters synthesized by bacteria under nutrient-limiting conditions. Soybean and palm oils are enzymatically hydrolyzed into fatty acids, which are subsequently metabolized by specific bacterial strains, such as Cupriavidus necator, to produce PHA. Palm oil, due to its high yield, is predominantly used in Southeast Asia. Non-edible castor oil is utilized for the synthesis of bio-based polyamides and polyesters, which are suitable for applications requiring enhanced mechanical properties and chemical resistance [40].
Agricultural residues such as rice husk, wheat straw, and corn stover are abundant sources of cellulose and hemicellulose. These residues are pre-treated to extract cellulose, which can then be transformed into cellulose acetate, a biodegradable polymer suitable for making films, fibers, and composites. Rice husk and wheat straw contain high amounts of cellulose, which is extracted via chemical or enzymatic processes. The extracted cellulose is used to produce biodegradable materials, such as cellulose acetate and cellulose-derived composites [41]. Food waste, including fruit and vegetable peels and spent grain from brewing industries, is a valuable resource for biodegradable polymer production. Pectin, starch, and other polysaccharides present in food waste can be processed to produce bioplastics. By-products from breweries, such as spent grain, are used to produce biodegradable polymers, contributing to value-added recycling. Waste cooking oils and fats, which are discarded from households and restaurants, are repurposed as substrates for microbial PHA synthesis. These oils are hydrolyzed into fatty acids, providing a carbon source for bacterial fermentation [42].
Microalgae are considered as efficient feedstock due to their high biomass productivity and ability to grow on non-arable land and wastewater. Microalgae produce lipids, proteins, and carbohydrates, which can be utilized for biopolymer synthesis. Lipids derived from microalgae can be utilized as carbon substrates for producing PHA. The carbohydrate fraction mainly composed of starch and polysaccharides can be fermented to produce PLA and other bioplastics [43]. Certain bacterial species, such as Cupriavidus necator, accumulate PHA under nutrient-limiting conditions, using various carbon sources. These bacteria can metabolize sugars, fatty acids, and even industrial waste substrates for PHA production. Bacteria such as (Halomonas bluephagenesis) are grown in fermentation reactors with excess carbon and limited essential nutrients to induce PHA synthesis, which is then extracted and processed into biodegradable materials [44]. The fermentation of different carbon sources significantly affects both the yield and the physicochemical properties of PHA. Simple sugars like glucose and sucrose are easily metabolized by microbes such as Cupriavidus necator, often resulting in high yields of short-chain-length PHA (scl-PHA) like PHB, which are stiff and brittle due to their high crystallinity. Fatty acids and plant oils, being more energy-dense, can produce medium-chain-length PHA (mcl-PHA) with flexible, elastomeric properties, ideal for applications requiring ductility. Industrial wastes such as crude glycerol or waste cooking oil offer low-cost alternatives but may introduce impurities that reduce yield or alter polymer composition, depending on microbial tolerance and metabolic versatility [45].
Lignocellulosic biomass, including wood chips, miscanthus (Miscanthus giganteus), and switchgrass (Panicum virgatum), is composed of cellulose, hemicellulose, and lignin. The cellulose and hemicellulose fractions are pretreated and hydrolyzed to release fermentable sugars that can be converted to PLA and PHA. The lignocellulosic feedstock is subjected to chemical, physical, or enzymatic pretreatment to deconstruct its complex structure. The released sugars are subsequently fermented to yield biodegradable plastics [46]. Chitin is a natural polysaccharide found in the exoskeletons of crustaceans, such as shrimp and crab. It can be processed into chitosan, which is used in the manufacture of biodegradable films and coatings. Chitosan exhibits antimicrobial properties, making it suitable for food packaging applications. Extracting chitin from crustacean shell waste also provides an opportunity to repurpose seafood by-products into high-value biopolymers [47].
The production of biodegradable plastics involves various methodologies, which can be broadly classified into fermentation-based processes, chemical synthesis, and compounding techniques [48].
Fermentation-based production is a biochemical process that employs microorganisms to convert biomass into biodegradable polymers. Two prominent biodegradable plastics produced through fermentation are PLA and PHA. PLA is synthesized by fermenting carbohydrate-rich feedstocks, such as glucose or starch, using lactic acid bacteria, notably Lactobacillus. The fermentation process converts sugars into lactic acid, which is subsequently polymerized into lactide and finally into PLA via ring-opening polymerization. This method offers several advantages, including the utilization of renewable resources, biocompatibility, and versatile applications in packaging and medical devices [49]. In contrast, PHA is a family of biodegradable polyesters synthesized by various bacteria, including Cupriavidus necator, which metabolize organic substrates such as plant oils, glucose, or fatty acids to produce PHA granules. The bacteria store these granules as energy reserves, which can be harvested and processed into usable plastic. Studies have investigated the optimization of PHA production using a newly isolated strain, Ensifer sp. HD34. Response surface methodology (RSM) was used to optimize key fermentation parameters, including carbon source concentration, pH, and incubation time. Through this statistical approach, a significant increase in PHA yield was achieved while reducing experimental trials. Studies have also highlighted the effectiveness of RSM in fine-tuning bioprocess conditions for enhanced microbial biopolymer production, offering a cost-effective and scalable solution for industrial applications [50]. The fermentation process allows for high biodegradability in diverse environments, making PHA a highly attractive alternative to conventional plastics. Moreover, advancements in metabolic engineering are enhancing the yields of these biopolymers by optimizing bacterial strains and fermentation conditions, thus improving the feasibility of large-scale production [51].
Chemical synthesis involves the polymerization of monomers derived from renewable or petrochemical sources to produce biodegradable polyesters such as PCL (polycaprolactone) and PBS (polybutylene succinate). PCL is synthesized through the ring- opening polymerization of 𝜀-caprolactone in the presence of a catalyst, resulting in a flexible polymer with excellent biodegradability. This synthetic pathway allows for precise control over molecular weight and crystallinity, leading to tailored material properties for specific applications. PCL’s mechanical characteristics make it suitable for use in various fields, including drug delivery systems and biodegradable packaging [52].
PBS is produced through the polycondensation of succinic acid and butanediol, both of which can be sourced from renewable biomass or synthesized through fermentation. The process involves heating the monomers at elevated temperatures to facilitate the formation of polyester chains. PBS exhibits favorable mechanical properties, including good thermal stability and flexibility, making it suitable for applications in agricultural films and food packaging. The ability to synthesize these polyesters from renewable resources significantly contributes to their environmental appeal and aligns with the principles of green chemistry [53].
Blending and compounding techniques are employed to enhance the properties of biodegradable plastics by mixing them with other materials. This method often involves combining biodegradable polymers with natural fibers, plasticizers, or other biodegradable materials to improve mechanical strength, flexibility, and processing characteristics. For instance, the incorporation of starch into PLA during the melt blending process can enhance its biodegradability and reduce production costs, making it a more sustainable option for various applications [54].
Natural fibers, such as jute or hemp, can also be blended with PHA to improve their mechanical properties while maintaining environmental benefits. The use of plasticizers, such as glycerol, in the production of PCL can significantly enhance flexibility and processability. These compounding techniques not only improve the performance of biodegradable plastics but also expand their potential applications in consumer goods, automotive parts, and construction materials [55]. García-García et al. (2024) investigated the life cycle assessment (LCA) of PLA/starch biocomposites, exploring the environmental impacts of varying starch contents (0–50 wt%) through melt blending and 3D printing applications. The LCA revealed that incorporating starch into PLA reduced the overall environmental impact, primarily by decreasing the carbon footprint compared to pure PLA. The study emphasized that renewable, biodegradable fillers like starch can improve the sustainability of bioplastics, making them more eco-friendly without significantly compromising material properties [56].
Extrusion and molding are critical techniques for shaping biodegradable plastics into final products. The extrusion process involves melting the polymer and forcing it through a die to create films, sheets, or other continuous shapes. This method is widely used in the production of biodegradable packaging films and agricultural films, where thin, flexible materials are required. Extrusion allows for efficient mass production and can be easily adapted to various polymer formulations [39].
Injection molding is another prevalent technique, whereby molten biodegradable polymers are injected into molds to create intricate shapes and structures. This method is particularly suitable for producing disposable items such as cutlery, containers, and automotive components. The ability to produce complex geometries with high precision makes injection molding a valuable technique in the biodegradable plastics industry. Blow molding, which involves inflating a molten plastic tube into hollow shapes, is also utilized for producing containers and bottles, thereby expanding the range of biodegradable products available on the market [57].
The increasing need to mitigate the environmental impact of conventional petroleum-based plastics has driven the advancement of biodegradable plastics. These materials are designed to degrade under specific environmental conditions, offering a promising solution to plastic pollution. The processing techniques used in the production of biodegradable plastics are crucial in influencing their structural properties, degradation rates, and overall performance, thereby determining their appropriateness for diverse applications. Key processing methods such as extrusion, injection molding, blow molding, thermoforming, and film casting, highlighting their mechanisms, advantages, and challenges have been reviewed earlier [58].
Extrusion is a commonly employed processing technique for biodegradable polymers, particularly in the fabrication of films, sheets, and profile products. In this process, polymer granules are introduced into the extruder and subjected to controlled thermal and mechanical energy. As the material progresses through the barrel under shear and elevated temperatures, it transitions into a molten state and is subsequently forced through a die to form a continuous profile. Upon exiting the die, the extrudate is cooled and solidified, followed by cutting or shaping to desired specifications. While extrusion offers advantages such as high throughput, versatility across polymer types, and efficient raw material usage, it presents technical challenges, including the necessity for stringent temperature regulation to avoid thermal degradation and ensuring homogeneous dispersion of additives [59].
Injection molding is a widely utilized manufacturing process for fabricating biodegradable plastic components with complex geometries and high dimensional accuracy. This technique involves the thermal softening of polymer pellets within a heated barrel, followed by high-pressure injection of the molten material into a precision-engineered mold cavity. The process sequence encompasses polymer feeding, melting, injection, mold cooling for solidification, and subsequent part ejection. Injection molding is well-suited for large-scale production due to its high repeatability and capability to produce intricate structures. Nevertheless, it presents challenges such as high capital expenditure for mold fabrication and processing limitations associated with the viscosity and thermal sensitivity of certain biodegradable polymers [60].
Blow molding is an established thermoplastic processing technique employed for the fabrication of hollow structures such as bottles and containers. The process commences with the formation of a preform, which is subsequently heated to its viscoelastic state and subjected to pressurized air within a mold cavity, enabling it to conform to the mold’s geometry. This is followed by cooling and ejection of the finished product. The method is characterized by high production efficiency and the capability to produce lightweight yet mechanically robust components. However, its application with biodegradable polymers is constrained by their rheological limitations and sensitivity to thermal and shear conditions [61].
Thermoforming is a widely utilized processing technique wherein a biodegradable plastic sheet is heated to a pliable forming temperature, positioned over a mold, and shaped using vacuum or pressure. This method is extensively employed in the fabrication of packaging components such as trays, blisters, and containers. The process encompasses sequential steps: thermal softening of the polymer sheet, molding under applied force, cooling to solidify the structure, and subsequent trimming of excess material. Thermoforming offers high production efficiency and design flexibility across a range of geometries. However, it is constrained by sheet thickness limitations, which may lead to non-uniform wall thickness in the final products [62].
Film casting is a widely utilized technique for producing thin films of biodegradable polymers, particularly for applications in packaging and barrier materials. This method enables precise control over film thickness and physicochemical properties. The process involves the extrusion of polymer granules, which are melted and subsequently cast onto a cooled casting surface. The molten polymer undergoes controlled solidification, followed by film collection onto rolls for storage or further processing. Film casting facilitates the fabrication of uniform, high-quality films with tailored characteristics. Nonetheless, achieving optimal cooling rates remains critical, as inadequate thermal regulation may lead to structural defects such as warping or thickness irregularities [63].
The performance of biodegradable plastics is heavily influenced by their environmental sensitivity. Factors such as moisture, temperature, and the presence of specific microorganisms play a crucial role in determining the degradation rate. For instance, the availability of moisture enhances microbial activity, while higher temperatures can accelerate the breakdown process. In terms of mechanical properties, biodegradable plastics can exhibit tensile strength and flexibility comparable to traditional plastics [64]. However, they may occasionally demonstrate lower impact resistance, depending on the specific type and formulation used. The thermal properties of these materials generally show lower thermal stability than their conventional counterparts, which affects their processing temperatures and suitability for various applications. The melting point can also vary based on the material composition, influencing manufacturing techniques [65].
Another important property is water sensitivity. Certain biodegradable plastics, particularly those based on starch, can be adversely affected by moisture, limiting their use in wet or humid conditions. In terms of non-toxicity, biodegradable plastics are designed to decompose without releasing harmful substances, thus contributing positively to environmental health. The shelf life of these materials varies according to their type and storage conditions; some may have shorter shelf lives due to their biodegradable nature. The barrier properties of biodegradable plastics are generally inferior to those of conventional plastics, which can limit their use in applications requiring moisture or oxygen barriers, such as food packaging. Furthermore, the degradation by-products of biodegradable plastics should ideally be non-toxic and environmentally benign, although the specific by-products can differ based on the material used [28].
Processing biodegradable plastics requires careful attention to processing conditions, including temperature and humidity, which may differ significantly from those required for traditional plastics. This aspect can influence the manufacturing process and the types of applications that can be pursued. However, the cost of biodegradable plastics tends to be higher than that of traditional plastics, primarily due to the sourcing of raw materials and the specific processing requirements involved in their production. These properties make biodegradable plastics suitable for various applications, including packaging, disposable items (such as cutlery and plates), agricultural films, and medical devices. As environmental concerns continue to grow, the demand for biodegradable materials is expected to increase. Many biodegradable plastics are subject to specific regulatory standards for biodegradability and compostability, such as ASTM D6400 and EN 13432, ensuring that they meet specific criteria before being marketed [66].
Biodegradable plastics have become a viable alternative to conventional plastics in a wide range of applications, addressing the need for sustainability and reduction of environmental impact. Figure 4 illustrates the diverse applications of biodegradable plastics across multiple sectors. These include packaging, disposable items, medical devices, textiles, electronics, automotive, construction, and consumer goods. Biodegradable plastics offer environmentally friendly alternatives in areas like surgical implants, geotextiles, and cosmetic packaging, promoting sustainability without compromising functionality in various industrial and consumer products. One of the most prominent sectors where biodegradable plastics are used is packaging. Packaging represents a significant source of plastic waste, and biodegradable alternatives provide a sustainable solution. For instance, food packaging such as containers, wrappers, and films made from biodegradable materials help reduce the burden of plastic pollution. These materials can break down naturally, minimizing their impact on the environment. Moreover, shopping bags made from biodegradable plastics have gained popularity in grocery and retail stores, replacing traditional plastic bags that persist in landfills and oceans for centuries. Biodegradable bottles which made from PLA are also becoming more popular and are particularly used for beverages such as water and juice. These bottles decompose much faster than conventional plastic bottles, making them an environmentally friendly choice [67].
Different applications of biodegradable plastics.
The agricultural sector is another area where biodegradable plastics have found widespread use. Mulch films are used to cover the soil to retain moisture, control weeds, and regulate soil temperature, are commonly made from polyethylene which contributing to plastic waste when not properly disposed. In contrast, biodegradable mulch films can be tilled directly into the soil, where they break down naturally, thereby eliminating the need for removal and reducing labor costs. This not only saves time and money but also mitigates soil contamination. Plant pots and seed coatings are also made from biodegradable materials, making them a sustainable choice for agriculture. These products decompose in the soil, eliminating waste and promoting plant growth. Biodegradable seed coatings help enhance germination while breaking down into non-toxic components that enrich the soil [68].
Disposable items represent a significant portion of plastic pollution, and biodegradable plastics are increasingly being used as alternatives in this category. Products like cutlery, plates, and cups are now made from biodegradable materials, offering an environmentally friendly option for disposable tableware. These products are particularly useful in events, parties, and outdoor gatherings, where the convenience of disposable items is needed without contributing to long-term pollution. Additionally, biodegradable straws and stirrers have become popular, especially following growing awareness of the harmful effects of plastic straws on marine life. By using biodegradable alternatives, the hospitality industry and consumers can significantly reduce their plastic footprint while still enjoying the convenience of single-use items [69].
The medical and healthcare sectors have also embraced biodegradable plastics for specific applications where traditional plastics have limitations. Surgical implants such as sutures, screws, and pins made from biodegradable polymers are commonly used in procedures that require temporary support within the body. These implants gradually degrade over time, eliminating the need for follow-up surgeries to remove them. This not only reduces the overall cost of healthcare but also minimizes patient discomfort and recovery time. In addition to surgical implants, biodegradable plastics are also used in drug delivery systems. Polymers such as PGA (polyglycolic acid) and PLGA (polylactic-co-glycolic acid) are used to create controlled-release formulations that release medication slowly as they degrade. This provides a consistent and targeted therapeutic effect, improving patient outcomes while reducing the frequency of administration [70].
The textile industry is also adopting biodegradable plastics in various forms, such as clothing fibers. Synthetic fibers like polyester contribute significantly to microplastic pollution, as they do not break down easily in the environment. Biodegradable alternatives such as PLA fibers provide a sustainable solution, offering similar performance characteristics while being less harmful to the environment. These fibers are used in clothing and other textile products, providing a eco-friendly option for consumers. In addition to clothing, nonwoven fabrics made from biodegradable plastics are being used in disposable hygiene products like diapers, wet wipes, and sanitary napkins. These items are designed for single use and thus generate significant waste, but biodegradable alternatives can help mitigate their impact by breaking down more quickly and safely [71].
Electronics is another sector where biodegradable plastics are being utilized. Many electronic devices contain components made of conventional plastics that contribute to electronic waste. Biodegradable casings for devices like mobile phone covers and other temporary electronic gadgets provide an alternative that can significantly reduce waste generation. These casings break down over time, reducing the long-term environmental impact of electronic devices. The automotive industry has also started using biodegradable plastics for interior components such as trim, panels, and upholstery. These materials help reduce the overall weight of the vehicle, which can improve fuel efficiency, while also being more sustainable compared to traditional plastics [72].
In the construction industry, biodegradable plastics are used for geotextiles. Geotextiles are materials used in construction to control soil erosion, stabilize slopes, and facilitate vegetation growth. Traditional geotextiles are made from synthetic fibers that can persist in the environment for long periods, posing potential environmental hazards. In contrast, biodegradable geotextiles decompose naturally after fulfilling their purpose, reducing the risk of pollution and contributing to soil health. These materials are particularly useful in landscape restoration projects, where they provide temporary support and then break down without leaving harmful residues [73].
The consumer goods sector has also seen a surge in the use of biodegradable plastics, especially in cosmetic packaging. The beauty and personal care industry relies heavily on single- use plastic packaging for products like shampoo bottles, cream jars, and cosmetic tubes. By switching to biodegradable alternatives, companies can significantly reduce the plastic waste generated by these products. Additionally, toys made from biodegradable plastics are becoming more popular, especially among environmentally conscious consumers. These toys are designed to break down more easily than traditional plastic toys, reducing their long-term impact on the environment and providing a more sustainable option for families [48].
Marine applications represent a critical area where biodegradable plastics can help address ocean pollution. Fishing nets and other marine gear made from biodegradable materials are being developed to reduce the environmental damage caused by lost or discarded plastic fishing equipment. Conventional fishing nets can persist in the ocean for decades, entangling marine life and damaging ecosystems. By using biodegradable alternatives, the fishing industry can significantly reduce the long-term impact of plastic waste on marine environments, contributing to healthier oceans and a more sustainable future [74].
Biodegradable plastics encounter several challenges, the predominant one being their degradation behaviour. Effective decomposition often necessitates specific environmental conditions, such as elevated temperatures, controlled humidity, and the presence of active microbial communities typically found in industrial composting facilities. In the absence of such conditions, degradation may be significantly delayed or incomplete. In natural environments, such as oceans and soils, they may degrade much slower. Another challenge is the production process, which can be resource-intensive, involving the use of crops like corn or sugarcane, leading to concerns about land use and food supply. Additionally, these plastics can still produce micro plastics if not fully degraded. Public awareness and proper waste management are also essential, but currently lacking, which hinders their effectiveness. Finally, the cost of biodegradable plastics is often higher than that of conventional plastics, limiting widespread adoption [75].
The several factors which highlight the some major issues of biodegradable plastic are:
Currently, biodegradable plastics, such as PLA and PHA, have production costs that range from $2,000 to $7,000 per ton [76]. This is significantly higher than the cost of conventional plastics like PE (polyethylene) and PP (polypropylene), which cost between $1,000 and $2,000 per ton. Plastics are derived from renewable sources like corn and sugarcane, while conventional plastics rely on fossil fuels. Although bioplastics are energy- intensive to produce, they offer environmental benefits, being compostable and reducing emissions. Their market share is currently small (1%), but costs are expected to decrease with innovation, making them more competitive in the future [77]. The raw materials for biodegradable plastics are often more expensive, For example, PLA is primarily derived from corn starch, which has a higher cost compared to petroleum, the primary feedstock for conventional plastics. While fossil-based plastics benefit from established, large-scale infrastructure, bioplastics production is still in its infancy, accounting for only about 1% of the global plastics market. The production process for biodegradable plastics is more resource-intensive. Bioplastics undergo fermentation processes to convert sugars into the necessary polymers, which require more energy and advanced technology compared to the straightforward cracking and polymerization used in conventional plastics production. Moreover, the economies of scale that have made fossil- based plastics inexpensive do not yet apply to biodegradable plastics. Larger production volumes could lower the per-unit cost, but current demand is too low to drive this transition [77].
Biodegradability of plastics refers to their ability to break down into water, carbon dioxide (CO2), and biomass through microbial action. However, the degradation of biodegradable plastics is highly dependent on specific environmental conditions. Industrial composting facilities, for instance, maintain high temperatures (50–60 °C) and humidity, creating an ideal environment for microbial degradation. Under these conditions, polymers such as PLA and PBAT (polybutylene adipate terephthalate) can break down more efficiently. However, in natural environments such as soil and marine ecosystems, the lack of optimized conditions such as controlled temperature, moisture, and microbial activity leads to significantly reduced degradation rates of biodegradable plastics, and in some cases, degradation may not occur at all. Furthermore, the breakdown process can be incomplete, leading to the release of microplastics or other degradation byproducts. This presents a significant challenge to biodegradability claims, as not all biodegradable plastics perform uniformly across different environments [78]. The assessment of the toxicity and chemical composition of conventional and biodegradable plastics, including PLA and PBS. One study employed in vitro bioassays to evaluate endocrine activity and cytotoxicity. Results revealed that biodegradable plastics leached complex chemical mixtures, some of which induced significant toxicological responses. Contrary to common assumptions, several biodegradable plastic products exhibited comparable or even higher toxicity than conventional plastics. The study concluded that the biodegradability of plastics does not necessarily correlate with lower environmental risk, emphasizing the need for stricter evaluation of biodegradable materials before commercialization [79].
Composting biodegradable plastics introduces further complexity, particularly when distinguishing between industrial and home composting. Many biodegradable plastics, such as PLA, require temperatures higher than those found in home composting systems (usually around 20–30 °C) and may not fully degrade within the typical composting cycle. This incomplete decomposition poses risks for compost quality, as plastic fragments could persist in the compost, affecting its suitability for agricultural use. Additionally, the presence of additives and non-biodegradable components in some biodegradable plastics can lead to contamination of the final compost product. Moreover, compostable plastics must meet stringent certification standards, such as EN 13432 or ASTM D6400, to ensure they break down within a set timeframe under industrial conditions. However, the lack of universally accepted standards for home composting and mixed plastic waste streams further complicates the management of biodegradable plastics, leading to environmental and practical challenges [80].
Biodegradable plastics, while promising as an alternative to conventional plastics, face significant regulatory and infrastructure challenges. A major regulatory hurdle is the lack of standardized definitions for terms such as “biodegradable,” “compostable,” and “bio-based.” This ambiguity complicates the development and enforcement of policies, as these terms are often misused or misrepresented. Additionally, diverse and non-harmonized testing standards for biodegradability across regions create inconsistencies in assessing the environmental performance of these materials. Misleading claims about biodegradability, commonly referred to as greenwashing, further undermine consumer trust and delay effective policy implementation. Furthermore, current regulatory frameworks in many countries fail to provide comprehensive support for biodegradable plastics, with some single-use plastic bans not distinguishing between conventional and biodegradable options, thereby restricting their adoption [81].
From an infrastructural perspective, the proper degradation of biodegradable plastics requires specific environmental conditions such as elevated temperatures, high microbial activity, and sufficient time which are typically unavailable in conventional waste management systems. The limited availability of industrial composting facilities and anaerobic digestion units capable of processing these materials poses a significant barrier. Additionally, the absence of efficient collection and sorting systems results in biodegradable plastics entering traditional recycling streams, causing contamination and reducing the quality of recycled materials. The high capital and operational costs associated with establishing dedicated facilities for biodegradable plastics further hinder their widespread adoption, particularly in developing regions.
Another critical challenge is the lack of public awareness regarding the appropriate disposal methods for biodegradable plastics. Improper disposal often results in these materials being sent to landfills, where the conditions are inadequate for their degradation, thereby negating their environmental benefits. Regional disparities in waste management infrastructure exacerbate the problem, with rural and underdeveloped areas lagging behind urban centres in their capacity to process biodegradable waste. Addressing these challenges requires harmonized regulatory standards, investment in infrastructure, and targeted public awareness campaigns to enable the effective integration of biodegradable plastics into sustainable waste management systems [82].
The future of biodegradable plastics is poised to revolutionize material science and waste management, paving the way for a sustainable future. Significant advancements in the development of bio-based polymers are expected, with researchers exploring innovative feedstocks such as agricultural residues, algae, and microbial biomass. These materials not only reduce dependence on fossil fuels but also align with circular economy principles by utilizing renewable and waste-derived resources. Genetic engineering and synthetic biology present promising strategies for the development of engineered microorganisms and tailored enzymes capable of synthesizing biodegradable polymers with enhanced efficiency. These approaches have the potential to reduce production costs, improve yield, and facilitate the scalable manufacturing of biopolymers by optimizing metabolic pathways and regulatory networks involved in polymer biosynthesis.
The next decade is likely to witness breakthroughs in the functional properties of biodegradable plastics, enabling their application in sectors beyond packaging, such as agriculture, medical devices, and electronics. For instance, innovations in biodegradable mulch films for agriculture could enhance soil health while reducing plastic contamination. Similarly, bioresorbable medical plastics are anticipated to play a transformative role in surgical implants and drug delivery systems, reducing the need for invasive removal procedures.
From a regulatory perspective, the establishment of harmonized global standards will drive innovation and market acceptance. Standardized definitions and certification schemes for biodegradability under various environmental conditions (e.g., marine, soil, industrial composting) will ensure that materials meet stringent environmental performance criteria. Governments and policymakers are expected to introduce economic incentives, such as subsidies and tax breaks, to encourage the adoption of biodegradable plastics while investing in the development of composting and recycling infrastructure.
Technological advancements in waste management systems, particularly AI-based sorting and automation, will improve the separation and processing of biodegradable plastics, minimizing contamination in recycling streams. For example Project OMNI, a collaborative initiative by Recycleye, Valorplast, and TotalEnergies, aimed to enhance the circularity of polypropylene (PP) food packaging through AI-driven sorting technologies. Over 18 months, the project developed an artificial intelligence and computer vision system capable of identifying and separating food-grade PP from household post-consumer waste. In a demonstration unit, the AI model, trained on waste collected from five locations in France, achieved a 50% successful pick rate of food-grade material with over 95% purity. Subsequent decontamination processes enabled the production of recycled PP suitable for high-end packaging applications, marking a significant advancement in mechanical recycling for food- contact materials [83]. The expansion of decentralized composting units in rural and underserved areas will provide a localized solution to managing biodegradable waste, promoting sustainable practices globally. Moreover, research into enzyme- and microbial-based degradation technologies offers the potential for on-demand biodegradation, even in environments lacking industrial composting facilities.
Public awareness and education campaigns will play a critical role in fostering responsible consumer behavior. Future initiatives may include comprehensive labeling systems that inform consumers about the appropriate disposal methods for biodegradable plastics. Integration of biodegradable plastics into Extended Producer Responsibility programs will further incentivize manufacturers to design eco-friendly products and take accountability for their end-of-life management.
The convergence of these advances, coupled with cross-sector collaboration, promises a transformative impact on plastic waste reduction, greenhouse gas emissions, and the preservation of natural ecosystems. As biodegradable plastics continue to evolve, they are set to become a cornerstone of sustainable material science, driving progress towards a cleaner, greener future.
The advancement of biodegradable plastics marks a critical milestone in the transition toward sustainable materials, offering viable solutions to the environmental and ecological burden associated with conventional petroleum-derived polymers. Progress in material science, particularly in the synthesis of biopolymers from renewable feedstocks, has significantly improved the mechanical properties, biodegradability, and economic viability of these alternatives. Biodegradable plastics have demonstrated notable potential in mitigating plastic pollution, lowering greenhouse gas emissions, and aligning with circular economy principles. Nonetheless, several challenges persist. Key among these is the variable degradation rates in natural environments, the technical and economic barriers to large-scale production, and the risk of microplastic generation during incomplete or surface-level degradation. Addressing these issues requires an integrated, multidisciplinary approach encompassing material engineering, microbial biotechnology, and regulatory frameworks.
The novelty of this review lies in its holistic evaluation of biodegradable plastics—not only from a material and environmental standpoint but also by incorporating emerging technological interventions such as artificial intelligence for waste sorting and synthetic biology for enhanced biopolymer production. Additionally, it critically examines the paradoxical role of biodegradable plastics in contributing to micro-plastic pollution, an area often overlooked in mainstream discourse. In summary, while biodegradable plastics represent a promising avenue for reducing environmental degradation, their successful deployment depends on continued innovation, robust policy support, and coordinated efforts among researchers, industries, and policymakers. A systems-level approach will be essential to fully realize their potential and to pave the way for a more sustainable and resilient future.
Krishan Kumar: Conceptualization, Investigation, Writing – original draft; Annu Khatri: Investigation, Writing – original draft, Data curation, Writing – review & editing; Indu Shekhar Thakur: Conceptualization, Supervision, Visualization, Writing – review & editing.
This research did not receive external funding from any agencies.
Not applicable.
Source data can be provided on request.
The authors declare no conflict of interest.
Authors and co-authors are grateful to Prof. PB Sharma, Vice Chancellor, Amity University Haryana, Gurugram, for necessary help and support related to completion of work. The authors acknowledge the use of QuillBot for language polishing of the manuscript.
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Article Type: Review Paper
Date of acceptance: June 2025
Date of publication: July 2025
DOI: 10.5772/geet.20250011
Copyright: The Author(s), Licensee IntechOpen, License: CC BY 4.0
© The Author(s) 2025. Licensee IntechOpen. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
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