Enhanced lactic acid production by Lactobacillus rhamnosus ATCC 7469 through simultaneous saccharification and fermentation from household food waste

Abstract

A large amount of household food waste (HFW) is generated yearly and may negatively impact the environment and human health. The recovery of value‐added chemicals lactic acid (LA) from HFW through anaerobic treatment is a promising approach. However, it remains a challenge to increase the LA yield. In this paper, the LA production from HFW was enhanced by Lactobacillus rhamnosus ATCC 7469 through simultaneous saccharification and fermentation (SSF). The results showed that the mixed commercial enzymes of plant enzymes (E1), animal proteases (E2), and glucoamylase (E3) were more conducive to LA production than those used separately. Compared to the separate hydrolysis and fermentation (SHF), the LA production increased by 14% in the SSF, and the glucose concentration showed different change rules. Additionally, an average LA concentration of 47.7 g L–1 was obtained by repeated batch fermentation through SSF. However, the maximum LA concentration decreased with the fermentation ongoing. The trend of decreasing LA production could be improved by repeated batch fermentation with supplementary inoculation.