Eliminated high lipid inhibition in the anaerobic digestion of food waste for biomethane production by engineered E. coli with cell surface display lipase

Food waste (FW) with high content of lipid typically inhibits anaerobic digestion (AD) and methane production. In this study, a novel whole-cell catalyst was created to degrade lipid by displaying lipase on the E. coli cells surface to improve FW anaerobic digestion. The methane production rose, going from 25.78 to 161.77 mL/g VS, with a greater VS removal rate of 66.3% compared to CK group (29.6%). Long-chain fatty acids (LCFAs) was similarly reduced from 1733.6 mg/L to 337 mg/L. Microbial community analysis showed the relative abundance of Acinetbacter and Hydrogenophaga were increased from 1.7% to 6.6% and 1.3%–4.9%, respectively for substrates degradation. The methanogenic Methanosarcina increased from 24.7% to 52.3% for methane production. This study provided a potential approach that might be used to lessen lipid inhibition and improve anaerobic digestion of food waste. [Display omitted] •A novel lipase biocatalyst based on cell-surface display system was developed.•The inhibited of high lipid for AD system was eliminated by the biocatalyst.•High efficiency of biomethane production was achieved in the system.•Microbial community was significantly changed after the system operated.