Biodegradation and detoxification of low-density polyethylene by an indigenous strain Bacillus licheniformis SARR1

Abstract

Plastics are synthetic polymers, which are frequently used in daily life for a wide range of purposes. These plastic wastes are accumulated and generate plastic pollution in the environment. It needs many years for complete deterioration in the environmental conditions. Biodegradation is the most promising method to treat plastic pollution, as the microorganisms utilize the low-density polyethylene (LDPE) as a sole source of carbon, and this indicates an innovative approach to manage the problem of plastic waste. The isolate SARR1 was identified as Bacillus licheniformis using the National Center for Biotechnology Information (NCBI) database. The isolate SARR1 showed an LDPE removal rate (K) of 0.069 g day−1 with a half-life of approximately 335.32 days to degrade LDPE strips. The biomass production was 0.98 ± 0.006 gl−1 (Xm) during the incubation of 30 days, and the percentage of crystallinity was significantly decreased from 71.69% to 50.78% due to biodegradation. The esterase and lipase activity of isolate SARR1 was studied using UV visible spectroscopy. The gas chromatography-mass spectrometry analysis confirmed the synthesis of acetone, diazene dimethyl, and carbamimidothioic acid, 1-methylethyl ester with different peak area percentages of 23.38%, 65.58%, and 11.04%, respectively. Seed germination study showed that the compounds formed after biodegradation of LDPE by bacterial strain SARR1 were eco-friendly.