Screening and identification of polyurethane (PU) and low density polyethylene (LDPE) degrading soil fungi isolated from municipal solid waste

Plastics have become an important part of modern life and are used in different sectors of applications like packaging, building materials, consumer products and much more. Many plastics are physically, chemically robust and cause waste management problems. Bioremediation is an important approach to waste reduction that relies on biological processes to break down a variety of pollutants. This is made possible by the vast metabolic diversity of the microbial world. To explore this diversity for the breakdown of plastics, in the present study several indigenous fungi were screened from municipal solid waste to check for its ability to degrade the polyurethane (PUR) and Low Density Polyethylene (LDPE) under in-vitro and in vivo studies. Several fungi proved their ability to efficiently degrade polyurethanes and Low Density Polyethylene (LDPE) in biodegradable studies. Vigorous activity was observed in the genus Fusarium oxysporum, Aspergillus fumigatus, Lasiodiplodia crassispora, Aspergillus niger, Penicillium sp. and Trichoderma harzianum capable of degrading this polymer display a zone of clearance around the growing culture on both PUR and LDPE growth medium. These isolates were analysed on Impranil DLN medium as the sole carbon source under both aerobic and anaerobic conditions. Aspergillus niger was able to degrade the polymer more activity in the PUR-A solid medium and PUR-L liquid medium than other fungal isolates. A. niger resulted in maximum decrease in percentage of elongation and tensile strength 2.94, 4.32, and 5.11 in LDPE sheets for 30, 60 and 90 days durations and 0.78, 1.44 and 2.18 in PUR sheets for 30, 60 and 90 days durations and 25.5 Mpa with breaking load 7.5, Percentage of elongation of 295 in LDPE and 12.9 Mpa with breaking load 5.8, Percentage of elongation of 186 in PUR sheets respectively. This study can be used as valuable microbial tool in the field of bioremediation to solve the inert polythene and plastic waste management.