INVESTIGATING POLYETHYLENE DEGRADATION BY BACTERIA AND FUNGI FROM SOLID WASTE DUMPSITE.

Abstract

Polyethylene wastes accumulating in the environment pose an ever increasing ecological threat as environmental pollutant. In this research, degradation of low density polyethylene by microorganisms from soil in solid waste dumpsite was investigated. Isolation of microorganisms was carried out from degrading polyethylene from soil at a dumpsite. Bacteria isolated were Bacillus subtilis, Micrococcus varians and Clostridium spp while the fungi isolated were Penicillium spp, Fusarium sambucinum and Aspergillus niger. The ability of the isolates to utilize low density polyethylene (LDPE) as sole carbon source for growth in liquid and solid culture media was investigated. The result showed an increase in all bacteria cell count in both liquid and solid media. At the end of 5months, the highest weight loss in polyethylene inoculated with bacterial isolates under liquid culture was observed with Bacillus subtilis (7.93%) followed by Micrococcus varians (7.33%) and the least was observed in Clostridium spp (5.53%). For fungal isolates, Fusarium sambucinum caused the highest weight loss (16.07%) followed by Penicillium spp (8.20%) and the least was found in Aspergillus niger (4.53%). Also, on the solid culture, the highest weight loss from polyethylene samples inoculated with bacterial isolates was observed with Bacillus subtilis (0.86%) followed by Micrococcus varians (0.73%) and the least was observed for Clostridium spp (0.47%). For fungi, Penicillium spp caused the highest weight loss (0.86%) followed by Aspergillus niger (0.53%) and the least was caused by Fusarium sambucinum (0.46%). This reveals that these microorganisms could degrade polyethylene sample but faster in liquid than solid medium.