Zhao Jihua, Ma Hongzhi, Wu Wenyu, Ali Bacar Mohammed, Wang Qunhui, Gao Ming, Wu Chuanfu, Xia Changlei, Qian Dayi, Chong William Woei Fong, Lam Su Shiung
Department of Environmental Science and Engineering, University of Science and Technology, Beijing, Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China.
Department of Environmental Science and Engineering, University of Science and Technology, Beijing, Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China; Key Laboratory of Pollutant Chemistry and Environmental Treatment, School of Chemistry and Environmental Science, Yili Normal University, Yining 835000, China.
Bioresour Technol. 2023 Jan;368:128375. doi: 10.1016/j.biortech.2022.128375. Epub 2022 Nov 19.
Substrate toxicity would limit the upgrading of waste biomass to medium-chain fatty acids (MCFAs). In this work, two fermentation modes of electro-fermentation (EF) and traditional fermentation (TF) with different concentration of liquor fermentation waste (20%, 40%, 60%) were used for MCFAs production as well as mechanism investigation. The highest caproate (4.04 g/L) and butyrate (13.96 g/L) concentrations were obtained by EF at 40% substrate concentration. TF experiments showed that the substrate concentration above 40% severely inhibited ethanol oxidation and products formation. Compared with TF mode, the total substrates consumption and product yields under EF mode were significantly increased by 2.6%-43.5% and 54.0%-83.0%, respectively. Microbial analysis indicated that EF effectively alleviated substrate toxicity and enriched chain elongation bacteria, particularly Clostridium_sensu_stricto 12, thereby promoting ethanol oxidation and products formation. Caproiciproducens tolerated high-concentration substrates to ensure normal lactate metabolism. This study provides a new way to produce MCFAs from high concentration wastewater.
底物毒性会限制废弃生物质升级转化为中链脂肪酸（MCFAs）。在本研究中，采用两种发酵模式，即电发酵（EF）和传统发酵（TF），使用不同浓度（20%、40%、60%）的酒糟废液来生产MCFAs并进行机理研究。在底物浓度为40%时，电发酵获得了最高的己酸盐（4.04 g/L）和丁酸盐（13.96 g/L）浓度。传统发酵实验表明，底物浓度高于40%会严重抑制乙醇氧化和产物生成。与传统发酵模式相比，电发酵模式下底物的总消耗量和产物产量分别显著提高了2.6% - 43.5%和54.0% - 83.0%。微生物分析表明，电发酵有效缓解了底物毒性并富集了链延长细菌，特别是严格梭菌属12，从而促进了乙醇氧化和产物生成。产己酸菌能够耐受高浓度底物以确保乳酸正常代谢。本研究为从高浓度废水中生产MCFAs提供了一种新方法。
