Bacterial Remediation of Polyethylene

Abstract

Improper disposal of commodity plastics e.g. polyethylene (PE) in the environment causes land pollution, soil infertility, is unsightly and poses dangers to plant and animal life. The current effort describes the bacteria mediated biodegradation of commodity plastics by Serratia marcescens marcescens without first subjecting the plastics to thermo-oxidative ageing. It further elaborates on the mechanism and breakdown that are involved in the biodegradation of PE. 90 ml of carbonless medium containing essential minerals and vitamins (minus carbon source) was measured into seven conical flasks and 2 g of powdered PE was poured into each flask. 5 ml of three overnight cultures of Serratia marcescens marcescens was measured into six flasks. The other flask served as the control. The samples were incubated at 30o C, 141 revolutions per minute (rpm) in a rotary shaker for four weeks to observe the degradation incidence. After 4 weeks, 5 ml of cell-free supernatant from Serratia marcescens marcescens culture was measured into a sterile conical flask to which 2 g of sterile PE was added. This was incubated at 30 oC & 141 rpm in a shaker for four weeks. It was discovered that, the supernatants from Serratia marcescens marcescens degrade PE faster than the bacteria with a percent of degradation of 37.5 in a month. The SEM micrographs revealed that the biodegradation of polyethylene occurs due to the presence of voids and pits, which indicates the bacteria feeding on the PE.