Disadvantages Of Biodegradable Plastic

The exponential growth of human population has led to buildup of huge amounts of non- degradable waste materials such as plastics across our planet. Plastic materials have become an essential part of contemporary life because of their many desirable qualities of strength, lightness, durability and low production costs. These non-degradable plastic materials accumulate in the environment at a rate of millions of tons per year. They affect the aesthetic quality of cities, water bodies and natural areas. Improper methods of disposal such as burying or burning of plastic materials release harmful or toxic pollutants into the environment and thereby endanger the biosphere. The recycled plastics have limited usage as their structure gets altered.

Bioplastics are natural biopolymers including chemically unrelated products that are synthesized and catabolized by various organisms during unbalanced growth. Currently, different types of biodegradable polymers are being studied for different applications including polyhydroxyalkanoates (PHAs), polylactide (PLA), poly(ε-caprolactone) (PCL), poly(p-dioxanone) (PPDO) and poly(butylene succinate) (PBS). The most extensively produced microbial bioplastics are polyhydroxyalkanoates (PHAs) and their derivatives., discovered at the beginning of the 20th century by Lemoigne. Polyhydroxyalkanoates (PHA) are polyesters of various hydroxyalkanoates, synthesized by many bacteria as inclusion bodies, which are lipid in nature. PHAs extracted from bacterial cells have properties similar to conventional plastics, such as polypropylene. Therefore, they are very good substitute of petrochemical

A simplest solution can be utilization of a broad range of agroindustrial waste and surplus materials as carbon feedstock for PHA biosynthesis. Cost-efficient PHA production based on such waste and surplus materials will also help the industries to overcome disposal problems. The genus Bacillus as known to possess the ability to produce variety of hydrolytic enzyme/s, could be exploited for cost-effective production of PHAs using various agro-industrial wastes directly i.e. without any pretreatment for its conversion to simpler sugars, thus reducing the time duration and overall cost of production. In view of this, the isolate was further evaluated for its ability to produce various enzymes like protease, amylase, cellulase and lipase. Isolated Bacillus flexus strain produced cellulose, amylase and protease. The results concluded that the hydrolytic enzymes produced by the Bacillus flexus isolate enabled it towards transforming these complex substrates to simple absorbable metabolites, and making them available for PHA production. Several reports are available in the literature on PHA production by various Bacillus sp. using agro-industrial wastes and surplus materials. PHA production from dairy industry wastes (whey), sugar industry wastes such as molasses, agro industrial wastes like wheat bran, rice chaff, fruit pulps, oil cakes; cane bagasse and starch are some of the recent