Enhanced Food Waste Chain Elongation for Caproate Production: Role of Inorganic Carbon and Optimization Strategies

Abstract

In this study, the role of inorganic carbon in chain elongation fermentation was investigated by examining its effects at different carbonate concentrations. The results demonstrated that higher yield of caproate (6.3±0.3 g/L - 7.4±0.2 g/L) was achieved with a NaHCO3 concentration of 2.5-5.0 g/L. Building upon these findings, a chain elongation process for food waste was developed. The caproate productions of control, CO2 and Na2CO3 trials were 4.6±0.2 g/L, 7.3±0.1 g/L, and 8.3±0.2 g/L, respectively. Chain elongation fermentation of food waste (1t TS) with Na2CO3 enhancement could synthesize 116.9 kg of caproate and 72.5 kg of carbon could be converted in caproate, accounting for 15.5% of the total organic carbon in the food waste. This study provided a comprehensive exploration of the chain elongation process for food waste, offering insights for further optimization and enhancement of food waste chain elongation performance coupling inorganic carbon utilization.