Biodegradation of cassava starch modified low density polyethylene by Bacillus cereus and Pseudomonas aeruginosa isolated from waste dumpsite

Abstract

Low density polyethylene (LDPE) is used for packaging and other industrial application is a significant source of environmental pollution. The present study was aimed at testing the ability of bacterial strains identified as Bacillus cereus and Pseudomonas aeruginosa to degrade LDPE. These strains were isolated from soil samples collected from dump site. All bacterial isolates were screened for their ability to degrade synthetic LDPE. Bacillus cereus and Pseudomonas aeruginosa produced weight loss percentages of 0.18% and 0.17% respectively and were used for further studies. The biodegradation was further enhanced by blending pellets of the LDPE (90, 80 and 70 %) with cassava starch (10, 20 and 30%). The screened bacteria isolates were incubated along with the cassava starch modified LDPE for a period of 60 days. Degradation was observed in terms of weight loss and tensile strength of the modified LDPE. Bacillus cereus and Pseudomonas aeruginosa achieved a maximum weight loss reduction of 42.01 % and 51.03 % respectively in LDPE modified with 30 % cassava starch. However, the highest weight loss reduction of 54.03 % in 30 % Cassava starch modified LDPE by the bacterial consortium. Tensile strength of 42.01% was achieved in LDPE containing 30% starch. Therefore these results show that the bacteria used in this study can colonize, utilize and modify LDPE as a sole carbon source, signifying the potential of Bacillus and Pseudomonas spp. to degrade LDPE film. This work would also pave way for future studies on biodegradation to resolve the universal pollution issues.