Bioplastic Production from Microbial Systems: Progress, Challenges, and Industrial Prospects

Jelang Jelku D. Sangma^1,2

¹Department of Food Science and Nutrition, University of Agricultural Sciences, GKVK, Bangalore, Karnataka, 560065, India

²AICRP-WIA, ICAR (CIWA), Bhubaneswar, College of Community Science, Central Agricultural University, Tura, Meghalaya - 794005, India

Corresponding Author Email: jelang.jelku3@gmail.com

DOI : https://doi.org/10.51470/ABF.2025.4.3.29

Abstract

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1. Introduction

The rapid growth in global plastic production over the past several decades has transformed modern society, enabling advancements in packaging, construction, transportation, healthcare, and consumer goods. However, the durability and resistance to degradation that make plastics so useful have also created severe environmental challenges. It is estimated that millions of tons of plastic waste enter terrestrial and marine ecosystems annually, contributing to soil degradation, ocean pollution, and the accumulation of microplastics in food chains [1]. Conventional plastics derived from petroleum resources persist in the environment for hundreds of years, creating long-term ecological and health concerns.Growing awareness of plastic pollution, combined with regulatory measures and public demand for sustainable materials, has intensified research into biodegradable alternatives. Bioplastics represent a promising solution because they are derived from renewable biological resources and are often biodegradable under natural or controlled conditions. Unlike petroleum-based plastics, bioplastics can be integrated into circular economy models, reducing dependence on fossil resources and minimizing environmental accumulation [2]. Among different bioplastic production approaches, microbial systems have attracted particular interest because microorganisms can synthesize biodegradable polymers using renewable feedstocks through fermentation processes. Certain bacteria naturally accumulate polymers as intracellular energy reserves, which can be harvested and processed into plastic-like materials. Microbial production offers additional advantages, including scalability, flexibility in feedstock utilization, and compatibility with waste valorization strategies [3]. Recent advances in biotechnology, synthetic biology, and metabolic engineering have significantly improved microbial polymer production efficiency. However, challenges related to production cost, scalability, and material performance remain barriers to widespread commercialization. Understanding the scientific and technological progress in microbial bioplastic production is therefore essential for developing sustainable alternatives to conventional plastics.

2. Types of Microbial Bioplastics

Microbial systems produce several types of biodegradable polymers that exhibit plastic-like properties suitable for industrial applications. These materials differ in chemical composition, mechanical properties, and production methods, allowing for diverse application possibilities.

2.1 Polyhydroxyalkanoates (PHAs)

Polyhydroxyalkanoates are the most extensively studied class of microbial bioplastics. They are intracellular polyesters produced by many bacterial species as storage compounds under nutrient-limited conditions, typically when nitrogen or phosphorus becomes scarce while carbon sources remain abundant. Under these conditions, bacteria channel excess carbon into polymer synthesis, accumulating PHAs as energy reserves that can later be metabolized when nutrients become available.

PHAs exhibit thermoplastic behavior similar to synthetic plastics such as polypropylene, making them suitable for conventional processing methods including extrusion and molding. The mechanical properties of PHAs can vary depending on monomer composition, resulting in materials that range from rigid to flexible [4]. This tunability allows production of materials suitable for packaging, agriculture, medical devices, and disposable consumer products, PHAs are biocompatible, making them particularly attractive for biomedical applications such as tissue engineering scaffolds, surgical sutures, and controlled drug delivery systems.

2.2 Polylactic Acid (PLA) Precursors via Microbial Fermentation

Polylactic acid is one of the most commercially successful bioplastics currently available. Although PLA itself is typically synthesized through chemical polymerization, its precursor, lactic acid, is predominantly produced via microbial fermentation. Lactic acid bacteria efficiently convert sugars derived from renewable biomass into lactic acid, which can then be polymerized to produce PLA.

PLA offers several favorable properties, including transparency, mechanical strength, and processability comparable to conventional plastics used in packaging and disposable goods. It has found widespread application in food packaging, disposable utensils, agricultural films, and increasingly in medical devices and 3D printing materials [5]. Research efforts continue to improve fermentation efficiency, reduce production costs, and develop microbial strains capable of utilizing low-cost or waste-derived substrates for lactic acid production.

2.3 Other Microbial Biopolymers

Beyond PHAs and PLA precursors, microorganisms produce a variety of biopolymers with potential plastic applications. Bacterial cellulose, produced by species such as Komagataeibacterxylinus, exhibits exceptional mechanical strength, high water retention capacity, and biocompatibility. These properties make it attractive for applications in biomedical materials, wound dressings, and specialty packaging [6]. Microbial exopolysaccharides, including xanthan gum, pullulan, and gellan gum, are widely used as stabilizers and film-forming agents in food and pharmaceutical industries. Although not conventional plastics, these materials demonstrate the versatility of microbial polymer production.

Ongoing research seeks to engineer microorganisms capable of synthesizing novel biodegradable polymers with enhanced mechanical and functional properties suitable for broader industrial applications.

3. Microbial Systems Used in Bioplastic Production

A wide range of microorganisms have been investigated for their capacity to synthesize biopolymers, with bacteria representing the most important production platforms. Selection of suitable microbial strains depends on factors such as polymer yield, substrate utilization, growth rate, and ease of cultivation.

3.1 Bacterial Producers

Bacteria remain the primary producers of microbial bioplastics, particularly PHAs. Species such as Cupriavidusnecator (formerly Ralstoniaeutropha) are widely studied due to their ability to accumulate large amounts of polymer, sometimes exceeding 70–80% of cell dry weight under optimized conditions. Other genera including Bacillus, Pseudomonas, and Azotobacter also contribute to PHA production research [7]. Some bacterial species can utilize a broad range of carbon sources, including plant oils, sugars, glycerol, and agricultural residues, enabling flexibility in feedstock selection. This adaptability is valuable for industrial processes seeking to reduce raw material costs.

3.2 Genetically Engineered Microorganisms

Advances in genetic engineering and synthetic biology have enabled development of engineered microbial strains capable of enhanced polymer production. Metabolic pathways have been modified to increase carbon flux toward polymer synthesis, reduce byproduct formation, and enable utilization of alternative substrates [8]. Common industrial microbes such as Escherichia coli and yeast have been genetically engineered to produce PHAs and other polymer precursors, offering advantages such as rapid growth and well-understood genetics. Engineered strains also allow production of customized polymer compositions tailored to specific material properties.

3.3 Photosynthetic Microorganisms

Cyanobacteria and microalgae represent emerging platforms for sustainable bioplastic production. These organisms use sunlight and carbon dioxide as primary inputs, potentially allowing polymer production with minimal reliance on agricultural feedstocks. Such systems could contribute to carbon-neutral or carbon-negative material production [9]. However, challenges related to productivity, cultivation scalability, and harvesting efficiency currently limit large-scale implementation of photosynthetic systems.

3.4 Fungi and Yeasts

Fungal and yeast systems are primarily used in fermentation processes producing bioplastic precursors such as lactic acid and other organic acids. These organisms can efficiently utilize complex substrates, including lignocellulosic biomass, making them attractive candidates for waste-based bioplastic production systems [10]. Research continues to explore fungal systems capable of directly producing polymeric materials or enhancing precursor synthesis.

4. Advances in Production Technologies

Recent developments in microbial bioplastic production technologies have significantly improved the efficiency and feasibility of polymer synthesis, although large-scale implementation still faces challenges. Modern production processes rely primarily on fermentation systems in which microorganisms convert carbon-rich substrates into intracellular polymers under carefully controlled environmental conditions. Optimization of fermentation parameters such as temperature, oxygen supply, nutrient balance, and carbon concentration has enabled higher biomass and polymer yields compared with early production systems [11]. Fed-batch and continuous fermentation strategies are increasingly being employed to enhance productivity and maintain stable microbial growth conditions. These methods allow gradual nutrient supply and prevent substrate inhibition, thereby improving overall polymer accumulation. In addition, advances in bioreactor design and process monitoring technologies now allow precise control of microbial growth conditions, reducing production variability and enhancing scalability [12]. Metabolic engineering has also played a critical role in improving productivity. Genetic modifications allow redirection of cellular metabolism toward polymer synthesis while minimizing competing pathways that reduce yield. Engineered strains can now utilize a wide range of inexpensive substrates, including agricultural residues, industrial by-products, and food-processing waste. The integration of waste-based feedstocks into production systems not only lowers costs but also supports circular bioeconomy principles by converting waste streams into valuable materials. Continued improvements in fermentation technology and strain engineering are essential to making microbial bioplastics economically competitive.

5. Downstream Processing and Recovery

One of the major cost contributors in microbial bioplastic production is downstream processing, which involves recovery and purification of polymers from microbial biomass. After fermentation, the polymer is stored within microbial cells, requiring cell disruption and polymer extraction before further processing can occur. Conventional extraction methods often involve solvent-based techniques that dissolve the polymer while removing cellular components. However, these methods can be expensive, energy-intensive, and environmentally unfavorable due to solvent toxicity and disposal concerns [13]. Alternative recovery strategies are being explored to reduce environmental impact and production costs. Mechanical disruption methods, enzymatic digestion of cellular material, and environmentally friendly solvent systems are increasingly investigated as potential solutions. Research efforts also focus on developing microbial strains with modified cell structures that facilitate easier polymer recovery. Innovations in downstream processing are critical because polymer recovery costs can account for a substantial portion of total production expenses. Improved extraction methods that are both cost-effective and environmentally sustainable will significantly influence the commercial success of microbial bioplastics.

6. Industrial Applications of Microbial Bioplastics

Microbial bioplastics are gaining attention across multiple industrial sectors due to their biodegradability and renewable origin. Packaging applications represent one of the largest potential markets, as industries seek sustainable alternatives to single-use plastics. Biodegradable films, containers, and disposable packaging materials derived from microbial polymers are increasingly adopted by environmentally conscious companies.In agriculture, biodegradable mulch films and controlled-release fertilizer coatings reduce plastic waste accumulation in soils while improving crop productivity. Biomedical applications also represent an important area of growth, as microbial polymers such as PHAs exhibit excellent biocompatibility and biodegradability. These materials are used in surgical sutures, tissue engineering scaffolds, drug delivery systems, and implantable medical devices, consumer goods such as disposable cutlery, food service items, and personal care products are increasingly manufactured using biodegradable materials. However, widespread adoption remains limited by higher production costs compared with petroleum-based plastics. Continued improvements in material performance and cost reduction are expected to expand industrial applications in the coming years.

7. Challenges in Industrial-Scale Production

Despite promising developments, several barriers continue to restrict large-scale commercialization of microbial bioplastics. The most significant challenge is economic competitiveness. Petroleum-based plastics benefit from well-established infrastructure and economies of scale, making them cheaper to produce. Microbial bioplastics often require more complex production and recovery processes, resulting in higher overall costs.Feedstock availability and price fluctuations also influence production feasibility. While renewable substrates are desirable, competition with food resources and seasonal variability may affect supply stability. Additionally, fermentation processes require energy inputs and careful operational control, contributing to production expenses. Material performance also presents challenges, as some bioplastics exhibit lower thermal stability or mechanical strength compared with conventional plastics. Infrastructure limitations related to composting and biodegradation management further complicate adoption, since biodegradable plastics require proper waste management systems to realize environmental benefits.

Addressing these technical, economic, and infrastructural challenges is essential for successful commercialization and global adoption of microbial bioplastics.

8. Future Prospects and Research Directions

The future of microbial bioplastic production is closely linked to advances in biotechnology, process engineering, and sustainable resource management. Ongoing research focuses on developing highly efficient microbial strains capable of producing polymers at lower cost while utilizing non-food, waste-derived, or carbon-neutral substrates. Photosynthetic microorganisms capable of converting carbon dioxide into biopolymers using sunlight offer exciting opportunities for carbon-neutral production systems.Integration of microbial bioplastic production into biorefineries, where multiple valuable products are generated from biomass, could significantly improve economic feasibility. Innovations in synthetic biology may enable production of customized polymers with improved mechanical and thermal properties, expanding their industrial applicability.

Furthermore, increasing regulatory support and consumer demand for sustainable materials are expected to accelerate commercialization efforts. Collaboration among researchers, industry stakeholders, and policymakers will be essential to develop infrastructure and market conditions necessary for widespread adoption.

9. Conclusion

Microbial systems represent one of the most promising approaches for developing sustainable alternatives to conventional petroleum-based plastics. Advances in microbial biotechnology, fermentation engineering, and metabolic pathway optimization have significantly improved the production of biodegradable polymers such as polyhydroxyalkanoates and fermentation-derived precursors of other bioplastics. These materials offer environmental advantages, including biodegradability, renewable sourcing, and reduced dependence on fossil resources, making them attractive candidates for addressing global plastic pollution challenges.

Despite substantial scientific and technological progress, commercialization of microbial bioplastics remains constrained by economic and technical barriers, including high production costs, complex downstream processing, and limitations in material performance. Continued research is required to optimize microbial strains, improve process efficiency, and develop cost-effective recovery technologies. Integration of waste-derived feedstocks and carbon-neutral production systems can further enhance sustainability and economic feasibility.

Acknowledgement

The author(s) gratefully acknowledge the support of the International Innovation Program for Post-Doctoral Fellow, Eudoxia Research University, USA and India, under registration ID ERU/IIP-PDF/REG/2024/293, for providing research support and academic resources that contributed to the completion of this work.

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