Risk and Remediation of Microplastic Pollution in Marine Life

Plastic demand is gradually increasing with time. Due to their low biodegradability rate, plastics gather in the environment. The accumulation of plastic has persisted for centuries, causing serious health problems in living organisms worldwide. Yearly, ~4.8 million tons of plastic accumulate in the ocean. Microplastic ~5 mm in diameter is common in global marine ecosystems, reported from several countries and oceans, even from the geographically isolated Antarctic and Arctic regions. The composition of microplastics includes polyethylene, polyacrylonitrile, polystyrene, polypropylene, polyamide, and polyvinyl, etc., which make up 92.4% of plastic wastes. From the surrounding environment, metal and persistent organic matter are absorbed in microplastics, serving as a path for heavy metal adulteration in the marine environment. Microplastics mistakenly eaten by marine organisms enter into food chain systems. The inhalation of microplastic causes several risks to marine organisms such as reproductive complications, liver inflammation, oxidative stress, reduce growth rate, and disturbed immune systems. Several techniques have been developed to identify microplastics from environmental samples. Microorganisms exhibit the potential to transform several compounds, including plastic materials. The microbes, attached to the plastic surface, secrete certain extracellular enzymes. That enzyme causes the hydrolytic cleavage of polymers and produces the biocompatible product, CO2 and water. The reported plastic-polymer-degrading bacteria such as Bacillus cereus, Kocuria palustris, Bacillus pumilus, and Bacillus subtilis exhibit a weight loss of 1%, 1.5%, and 1.7%, respectively, after 30 days of incubation. Species like Brevibacillus borstelensis, Pseudomonas putida, P. stutzeri, Alcaligenes faecalis, etc., condense synthetic plastic. Bioremediation of plastic polymers makes these microorganisms more optimistic about green chemistry.