BIODEGRADATION OF LOW-DENSITY POLYETHYLENE (LDPE) BY STAPHYLOCOCCUS KLOOSII M1 ISOLATED FROM CATTLE DUNG

Polyethylene has become a serious environmental pollutant due to its high non-biodegradability and has gained the attention of several researchers to find a way to degrade it.Large numbers of animals die due to ingestion of plastic material annually.Stray cattle also badly suffer due to the ingestion of plastics.Approximately 1.5 million marine animals died due to blockage of air passage and 1 million birds died due to ingestion of plastics annually [1,2].The use of physical and chemical methods to degrade plastic wastes results in the emission of polychlorinated biphenyls, polycyclic ABSTRACT: This study aimed to isolate bacteria from cattle dung for the biodegradation of low density polyethylene (LDPE).Cattle dung were collected from the Instructional Livestock Farm Complex (ILFC), Veterinary College, Mhow, Madhya Pradesh.LDPE films were treated with UV rays for 48 hours and used for the study.Three isolates were identified by Gram's staining.Out of three isolates M1, S1 and K4; two were identified as Gram-positive, and 1 was found as Gram-negative bacteria.Screening of isolates for LDPE biodegradation was carried out using a clear zone method.Out of 3 isolates, M1 was identified as LDPE degrading bacteria.LDPE degradation was analysed by gravimetric analysis using the weight loss method, functional group analysis by Fourier transform infrared (FT-IR) spectroscopy and surface analysis by scanning electron microscopy (SEM).After 60 days of incubation with LDPE films isolate M1 showed significant weight loss (8.08 1.03 %).FT-IR analysis showed a decrease (22.64%) in carbonyl index and changes in functional group vibrations indicating LDPE degradation.SEM image examination revealed bacterial colonization, biofilm formation, surface erosions, cracks and pit formation on the LDPE surface which was indicative of the degradation of LDPE film.Further, the identification of isolate M1 was done by BD Phoenix M50 automated identification and susceptibility testing system and 16S rRNA sequencing.Sequencing and phylogenetic analysis of the M1 isolate showed 98.83% similarity with Staphylococcus kloosii strain ATCC 43959 chromosomes (Accession No. OR771911.1).Our findings underscore the potential of strain M1 from cattle faeces to efficiently utilize LDPE as a sole carbon source, thereby contributing to its degradation.This is the first report of isolating LDPE-degrading bacteria from cattle faeces.It is crucial to analyse the cattle dung gut microbiota for plastic degradation since this discovery highlights the need for further investigation.