Chain Elongation Significantly Contributes to N-Butyrate Production in Anaerobic Fermentation of Food Waste Saccharified Residue: Effect of Substrate Content

Abstract

In this study, food waste saccharified residue was used to produce volatile fatty acids (VFAs), and the effects of substrate content on VFA production, VFA composition, acidogenic efficiency, microbial community, and carbon transfer were investigated. Interestingly, chain elongation from acetate to n-butyrate played an important role with a substrate content of 200 g/L in the acidogenesis process. Results showed that 200 g/L was a suitable substrate content for both VFA and n-butyrate production, the highest VFA production, and n-butyrate composition were 280.87 mg COD/g VS and more than 90.00%, respectively, and VFA/SCOD reached 82.39%. Microbial analysis showed that Clostridium_Sensu_Stricto_12 promoted n-butyrate production by chain elongation. Carbon transfer analysis indicated that chain elongation made a contribution of 43.93% to n-butyrate production. Totally 38.47% of organic matter in food waste saccharified residue was further utilized. This study provides a new way for n-butyrate production with waste recycling and low cost.

Keywords: Food waste saccharified residue, Anaerobic fermentation, n-Butyrate, Substrate content, Chain elongation