Promoting the anaerobic production of short-chain fatty acids from food wastes driven by the reuse of linear alkylbenzene sulphonates-enriched laundry wastewater

An efficient attempt to improve the anaerobic fermentation of food wastes (FW) via the reuse of linear alkylbenzene sulphonates (LAS)-enriched laundry wastewater was reported. The production of short-chain fatty acids (SCFAs) from FW was enhanced by approximate 6-folds with high proportions of butyric and valeric acids at appropriate LAS level. Mechanism investigations demonstrated that the solubilization of macromolecule organics in FW was effectively improved by surface tension reduction. The hydrolysis and acidification processes during FW fermentation were accelerated and enhanced with the stimulation of microbial activities (higher activities of hydrolases and ATP concentrations). Also, the abundances of anaerobic microorganisms responsible for SCFAs production were enriched. Metatranscriptomic analysis indicated that the encoding genes involved in the metabolism of fermentation substrates for SCFAs production were highly expressed in LAS-added reactors. It was the simultaneous increase of bioavailable substrates and metabolic activities that contribute to the efficient SCFAs production in LAS-added reactors.