Isolation of polyolefin’s degrading bacteria from compost

Abstract

The present study was done on the isolation of polyolefin-degrading bacteria from compost. Several bacterial strains were isolated by two techniques: (i) enrichment technique for PE and PP powder; (ii) by incubating PE and PP film in synthetic media.

By enrichment technique, five bacterial strains were isolated, four degrading PP and one degrading PE. PP degrading bacteria were found to be Gram positive and PE degrading bacteria was found to be Gram negative bacteria. O.D at 600 nm and CFU/ml count were also measured to see the growth of microorganisms in synthetic media. The increase in O.D and CFU/ml count indicates the utilization of the given polymer as the carbon source. Higher growth was found in PE as compared to PP. This shows that PP is more resistant to biodegradation than PE, due to presence of extra methyl group.

After two months of incubation of PE and PP films in synthetic media, several bacterial strains were isolated, 6 degrading PE & 5 degrading PP. Their weight loss was measured. Higher weight loss was observed in PE (1.95%) than PP (1.2%). This is also supporting the fact that PP is more resistant to biodegradation than PE. The efficacy of isolated microbes in the degradation of plastics were analyzed in liquid (shaker) culture method. As the growth of microbes proportionally increased in synthetic media, so the microbes were solely dependent on polymer films for its C-source. FTIR also confirmed for the degradation of polymer by compost.