Amid the growing plastic pollution crisis, biodegradable bioplastics are considered a sustainable alternative. These materials decompose under the natural action of microorganisms, enzymes, temperature, and humidity. The process is not simply that plastics “disappear,” but involves multiple complex biochemical stages. Let’s explore the detailed phases of decomposition, the influencing factors, and the most common types of biodegradable plastics today.
HOW DO BIODEGRADABLE PLASTICS DECOMPOSE?
Biodegradable plastics do not automatically vanish in the environment. Instead, they undergo a series of biochemical reactions involving bacteria and fungi. This process is typically divided into four main stages.
Initial Disintegration (Hydrolysis)
Once the polymers are fragmented, the resulting products are monomers and oligomers. These smaller compounds are absorbed by bacteria or fungi as energy and nutrients. Through assimilation, microorganisms transform organic molecules into part of their living structure, preparing for mineralization.
Bioassimilation
Sau khi polymer đã bị phân cắt, sản phẩm thu được là các monomer và oligomer. Các hợp chất nhỏ này được vi khuẩn hoặc nấm hấp thụ làm nguồn năng lượng và chất dinh dưỡng. Nhờ khả năng đồng hóa, vi sinh vật biến các phân tử hữu cơ thành một phần cấu trúc sống, chuẩn bị cho giai đoạn khoáng hóa.
Mineralization
This is a vital stage where organic compounds are converted into inorganic substances. In aerobic conditions, microorganisms fully oxidize them into CO₂ and water. Under anaerobic conditions, the process generates CH₄ along with CO₂. The end products are harmless compounds that restore balance to ecosystems.
Biomass Formation
Beyond producing gases and water, a portion of the biodegradable plastic is converted into new microbial biomass. This means part of the material becomes microbial cells, contributing to biodiversity in natural environments.
FACTORS INFLUENCING THE DECOMPOSITION RATE
Temperature
At high temperatures, particularly 55–70°C in industrial composting, decomposition accelerates significantly. This is why biodegradable plastics are often processed in composting facilities rather than left directly in nature.
Moisture
Enzymes and microorganisms need water to function. In overly dry conditions, bioplastics degrade very slowly. With sufficient moisture, biochemical reactions speed up.
Microorganisms
Bacteria and fungi such as Pseudomonas, Bacillus, Aspergillus, and Penicillium play a key role. They secrete enzymes that break down polymers and assimilate monomers into energy.
Polymer Structure
Plastics with linear chains, low crystallinity, and functional groups such as esters or urethanes are more easily degraded. Highly crystalline or branched polymers degrade much more slowly.
COMMON TYPES OF BIODEGRADABLE PLASTICS
PLA (Polylactic Acid)
PLA is among the most widely used biodegradable plastics. It decomposes well under industrial composting conditions where temperature and humidity are controlled. PLA is used in packaging, food containers, disposable cups, and fibers. However, it degrades slowly in natural environments such as soil or marine ecosystems.
PBS and PBAT
PBS (Polybutylene Succinate) and PBAT (Polybutylene Adipate Terephthalate) combine flexibility with high mechanical strength. They degrade easily in aerobic environments and are commonly used for biodegradable bags, agricultural films, and packaging materials. Thanks to their versatility, PBS and PBAT are increasingly adopted in green packaging industries.
PHA (Polyhydroxyalkanoates)
PHA is produced directly by bacteria through the fermentation of sugars or vegetable oils. Its unique advantage is the ability to decompose in soil, freshwater, and marine environments. This makes PHA a highly promising material for eco-friendly products, from packaging and biofilms to biomedical applications.
THE ROLE OF BIODEGRADABLE PLASTICS IN MANUFACTURING AND SUSTAINABLE DEVELOPMENT
Biodegradable plastics support manufacturers in shifting to green materials, lowering waste treatment costs, and meeting international environmental standards. For sustainable development, they help reduce plastic waste, utilize renewable raw materials, and lessen dependence on fossil resources. As green consumption trends rise, products made from biodegradable plastics enhance competitiveness and open new export opportunities for businesses.
VICHEM – OFFICIAL DISTRIBUTOR OF CERTIFIED CHEMICAL ADDITIVES IN VIETNAM
Vichem is an authorized distributor of chemical additives, fully compliant with legal requirements in Vietnam. We not only provide quality products but also deliver international-standard after-sales services. Our services include:
- Technical consulting: Helping customers choose the right product samples for their applications.
- Color matching tests: Our expert team conducts testing to ensure results meet design standards.
- Practical application support: Assisting clients in integrating materials into production lines for optimal efficiency.
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