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 biode gradation 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 biode gradation 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 asthe 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 30oC & 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 degradationof 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.
CHAPTER ONE
1.0 INTRODUCTION
1.1 Background
The world has an abundance of land and resources [1]. However, due to human carelessness and negligence, we have contaminated the environment. Industrial activities generated from the past have resulted in polluted lands and landfills that are potentially harmful to the health and wellbeing of people [1]. There is, therefore, a need for improved methods of waste disposal that could limit the long term effects on human wellbeing. Plastics are artificially made long chain ―polymeric molecules‖ and come from the Greek word ―Plastikos‖, indicating that they are able to form different shapes [2].
