Cyanobacterial degradation of low-density polyethylene (LDPE) by Nostoc carneum isolated from submerged polyethylene surface in domestic sewage water

Abstract

A heterocystous cyanobacterial isolate Nostoc carneum was found to be capable of degrading low-density polythene utilising it as a carbon and energy source. The structural, morphological and chemical changes of the degraded PE were monitored by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy, nuclear magnetic resonance (NMR) spectroscopy, CHN microanalyses and tensile strength measurements. The TGA-DSC and CHN microanalyses corroborated about 3% carbon utilisation by Nostoc carneum from the PE. The higher generation time of the cyanobacterium on PE substrate vis-a-vis the biotic control augmented PE carbon utilisation by the species. The diagnostic features for alcohol and ester were observed in FT-IR and NMR spectra as the end products of biodegradation. The bond indices and enzyme activity further furnished evidence for PE degradation. Formation of holes and cavities on the surface of the PE indicated the disruption and reduction in the polyethylene integrity. The cellular constituents and enzymatic activities of the PE grown cells indicated a possible role of the enzymes in biodegradation.