Ecofriendly Degradation of Polyethylene Plastics Using Oil Degrading Microbes

Abstract

Background & Objective: Plastics are strong, light weight and durable due to which it has wide applications. Degradation of plastics is difficult due to their xenobiotic origin and recalcitrant nature. Hence, accumulation of plastics in the environment is posing an increasing ecological threat. Methods: Various methods are preferred for the reduction of plastics in the environment, of which degradation by chemical and biological means are considered to be more effective. In the biodegradation of plastics, micro organisms play a pivotal role. In the present work, microbial species are isolated from different sources such as cooking oil, grease and petroleum products. Two bacterial species such as Sphingomonas, Pseudomonas aeruginosa and three fungal species such as Aspergillus niger, Aspergillus flavus and one unidentified fungal species were isolated from the sources were used for the degradation of polyethylene plastic samples (black and white). Results: Sphingomonas indicated 56% (black) and 31% (white) degradation of polyethylene plastic. Unidentified fungal species also indicated 64% (black) and 45% (white) degradation of polyethylene plastic. During the degradation, pH altered from 7 to 8. SEM analysis indicated the presence of appreciable surface erosions, fading, cracks and extensive roughening of the surface with pit formation. Conclusion: Sequence analysis of Sphinogomonas species was done in comparison with the similar known bacterial species and the phylogenetic tree was generated based on the sequence analysis.