Biodegradation Of Plastics Using Fungal Isolates
The list of pollutants which pose environmental and health hazard are tough for biodegradation, is a long one and involves solvents, wood preservative chemicals, refrigerants, plasticizers, coal tar wastes, pesticides, biphenyls, synthetic fibers, plastics etc. The present study deals with the isolation of plastic degrading microorganisms from the plastic samples, analysis of physical or changes produced during biodegradation and the study of enzymes involved in biodegradation. The polymer polyethylenes of three different densities (LLDPE, LDPE & HDPE) were used in the study. Nine fungal species were isolated from the plastic sample isolated from the outskirts of Amrita School of Biotechnology, Amritapuri. The three kinds of polyethylene were then subjected for fungal action for 2 months in PDB. Weight of the plastic inoculum was taken at the beginning of the experiment. At the end of two months, the plastic beads were isolated from the media, washed and shade dried. The beads were then weighed. Characteristic weight loss obtained. This proves the hypothesis of plastic polyethylene biodegradation by fungi. For further clarity of the study, electron micrograph of the sample treated with the fungal species was obtained. Enzymes are key players in the process of biodegradation. Lignin peroxidase is the most suspected extracellular enzyme. LiP assay was carried out by TLC method using veratryl alcohol as substrate. Very low concentrations of LiP were detected in the samples.