Lactic acid production from mesophilic and thermophilic fermentation of food waste at different pH.

Luxin Yang, Liang Chen, Huan Li, Zhou Deng, Jianguo Liu

Journal of environmental management 2022 Feb 15

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It is promising to recover lactic acid (LA) from fermentation of food waste (FW). In this study, pH and temperatures were investigated comprehensively to find their effects on LA fermentation, and microbial analyses were used to take insight to the variation of LA production. The results showed that mesophilic fermentation benefited hydrolysis and acidification, leading to a high yield of LA, while thermophilic conditions restricted other producers at low pH, leading to a high purity of LA. Lactobacillus amylolyticus was the main LA producer under thermophilic conditions, but Thermoanaerobacterium thermosaccharolyticum boomed at pH 5.0-6.0 and it converted LA partly to butyric acid. Simultaneously, Bacillus coagulans also increased and improved the optical purity (OP) of L-LA. From a series of this study, an operational condition of pH 5.5 and temperature of 52 °C would be potentially suitable for lactate fermentation of FW with high purity of 89%, while a stable LA production with an OP of 68% was achieved at 55 °C and pH 6.0. Copyright © 2021 Elsevier Ltd. All rights reserved.

Citation

Luxin Yang, Liang Chen, Huan Li, Zhou Deng, Jianguo Liu. Lactic acid production from mesophilic and thermophilic fermentation of food waste at different pH. Journal of environmental management. 2022 Feb 15;304:114312