Biodegradation of used polyethylene bags by a new marine strain of Alcaligenes faecalis LNDR-1.

ABSTRACT

Disposable plastic bags of two different chemical compositions and colors were remediated by the application of novel mesophilic group of bacteria isolated from the banks of sea water, using a 10 week soil burial method. The new strain, LNDR-1, was identified as Alcaligens faecalis by its morphological features and 16S rRNA sequencing. LNDR-1 was able to produce extracellular enzymes such as lipase, CMCase, xylanase, and protease, having PET surface degrading activity. It was found that LNDR-1 had a better decay rate of 15.25 ± 1% and 21.72 ± 2.1% for black and white plastic bags respectively in 10 weeks without prior oxidation as compared to S. marcescens. Polyethylene degradation was confirmed by substantial weight loss, alterations in surface topology, and hydrophobicity index and was found to be directly proportional to the ability to form biofilm on the plastic surface. FTIR results suggest presence of different metabolites in the bags treated with bacterial biofilm in comparison to the control setup inferring various types of metabolic pathways. Present study also reveals the ability of the strain to utilize the used polyethylene bag as the carbon source, without any prior treatment, and as per the literature survey, the working strain is with the capacity to biodegrade plastic at a considerably appreciable rate. This study suggests effectual method for the mechanism of biodegradation of plastic mediated by extracellular enzymes and formation of biofilm.