Plastic Biodegradation

Biodegradation of plastics and polymers in the environment.

What is Biodegradation?

Biodegradation is defined by the EPA as, “A process by which microbial organisms transform or alter (through metabolic or enzymatic action) the structure of chemicals introduced into the environment.”

Organic (carbon-based) material is changed through chemical processes from complex molecules into simpler molecules, eventually returning the molecules into the environment. For example, a banana peel can be reduced from cellulose to water, carbon dioxide gas, and humus in a compost pile.

The biodegradation process breaks down everything from yard waste to crude oil. It is a natural process that keeps our planet clean and healthy. Unfortunately, the rate at which we are producing waste far outpaces the rate of natural biodegradation, leading to an unsustainable state. As landfills fill up at record rates, air, water and soil pollution is increasing.

Normal Plastic Biodegradation

Plastics is a broad name given to different polymers that high molecular weights. The vast majority of plastics produced today are made from nonrenewable petrochemicals, so named because they are derived from fossil oil, natural gas, and coal. Although these plastics are inexpensive, each is a highly engineered material with precise physical properties. They can be molded into virtually any desired shape through various means.

Common plastics biodegrade very slowly. So slowly that most plastics and polymers are considered non-biodegradable. Plastic degradation rates can vary widely depending on the exact type of plastic. Most plastics biodegrade in roughly 200-1000 years in a landfill or natural environment, Estimates of degradation times for plastic bags range from 100–500 years, while plastic bottles are reported as over 200 and up to 450 years.

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Phases of Biodegradation with EcoPure®

The process of biodegradation happens naturally over time. Depending on the material, the timeline to full degradation can vary. With plastics, this process usually takes hundreds to thousands of years to complete, if ever, because of the strong polymers that makes up the chemical structure of plastics.

However, with Bio-Tec Environmental LLC’s organic plastic additive, EcoPure®, the process is significantly accelerated. EcoPure® plastics complete the biodegradation* process at much higher rates, which includes:

Aerobic Phase

In this phase, the enzymes and decomposition chemicals act as a catalyst to the biofilm coating the plastic. During this time, aerobic microbes are becoming established and moisture is building up in the refuse. Standard plastic moisture absorption capability is relatively small, but the additive causes further swelling, weakening the polymer bonds. This creates molecular spaces for microbial growth, which begins the aerobic degradation process in which oxygen is converted to CO2.

Anaerobic, Non-Methanogenic Phase

After oxygen concentrations have declined sufficiently, the anaerobic processes begin. During the initial stage (hydrolysis), the microbe colonies eat the particulates, and through an enzymatic process, reduce large polymers into simpler monomers. The organic additive causes additional swelling and opening of the polymer chain and increased quorum sensing. This further excites the microbes to increase their colonization and consumption of the polymer chain. As time progresses, acidogenesis occurs where the simple monomers are converted into fatty acids. CO2 production occurs rapidly at this stage.

Anaerobic, Methanogenic Unsteady Phase

The microbe colonies continue to grow, eating away at the polymer chain and creating increasingly larger molecular spaces. During this phase acetogenesis occurs, converting fatty acids into acetic acid, carbon dioxide and hydrogen. As this process continues, CO2 rates decline and hydrogen production eventually ceases.

Anaerobic, Methanogenic Steady Phase

The final stage of decomposition involves methanogenesis. As colonies of microbes continue to eat away at the remaining surface of the polymer, acetates are converted into methane and carbon dioxide, and hydrogen is consumed. The process continues until the remaining element is humus. This highly nutritional soil creates and improved environment for the microbes and enhances the final stage of decomposition.

Frequently Asked Questions

What is Aerobic and Anaerobic Biodegradation?BoostAdmin2023-03-19T05:32:39-06:00

What is Aerobic and Anaerobic Biodegradation?

Aerobic biodegradation involves the breakdown of organic matter by microorganisms in the presence of oxygen. Anaerobic biodegradation is the breakdown of organic matter by microorganisms when oxygen is not present.

What are Biodegradable Plastics?BoostAdmin2023-03-19T05:32:39-06:00

What are Biodegradable Plastics?

Biodegradable plastics are defined by the American Society for Testing and Materials (ASTM) as “a degradable plastic in which the degradation results from the action of naturally-occurring microorganisms such as bacteria, fungi, and algae”.