Microbial Consumption of Plastics: A Prospective Solution for Plastic Mitigation

In our current lifestyle, plastics place a very important role; therefore, its gathering in the environment is major alarms that harm the human health. Petroleum-derived plastics such as PE, PET, PU, PS, PP, and PVC are awfully recalcitrant to natural biodegradation pathways. Large number microorganisms have the capacity to degrade petro-polymers under natural as well as lab conditions which have been investigated by different scientists. The enzymes produced by different microbes have been genetically engineered. The polymer biodegradation rate depends on various factors like molecular weights, chemical structures, and degrees of crystallinity. These are bulky molecules having crystals as well as irregular groups that provide hardness and flexibility to the polymers. Polyethylenes (95%) are rigid, highly crystalline polymers with a limited capacity to oppose impact. Crystallinity of a polymer (30–50%) in plastic is a main cause of slow microbial degradation. The microbial degradation as well as enzymatic degradation occurs via enzyme adsorption on the surface of polymer, followed by hydro-bond peroxidation and hydrolysis. The petro-plastic disintegration or depolymerization into polymer monomers for different purposes like recycling or converting waste plastics into higher-value by-products is considered as a promising strategy. Finally, plastic degradation can be measured by applying different techniques like SEM, TEM, FTIR, TGA, UV spectroscopy, DSC, HPLC, etc. The purpose of this section is to sketch the different categories of plastic, their impact on environment, the impact of microbes, or their enzymes toward the degradability of synthetic plastics to clean up the environment.