Low-temperature caproate production,microbial diversity,and metabolic pathway in xylose anaerobic fermentation  

作　　者：Qingting Wang Kun Dai Jie Tang Sidi Hong Sijie Zheng Ting Sun Raymond Jianxiong Zeng Fang Zhang 

机构地区：[1]Center of Wastewater Resource Recovery,College of Resources and Environment,Fujian Agriculture and Forestry University,Fuzhou 350002,China

出　　处：《Frontiers of Environmental Science & Engineering》2023年第3期121-130,共10页环境科学与工程前沿（英文）

基　　金：the National Natural Science Foundation of China(Nos.51808120 and 52170127);China Postdoctoral Science Foundation(No.2019M652235);the Program for Innovative Research Team in Science and Technology in Fujian Province University(China)(IRTSTFJ).

摘　　要：Mixed culture fermentation(MCF)is challenged by the unqualified activity of enriched bacteria and unwanted methane dissolution under low temperatures.In this work,caproate production from xylose was investigated by MCF at a low temperature(20°C).The results showed that a 9 d long hydraulic retention time(HRT)in a continuously stirred tank reactor was necessary for caproate production(~0.3 g/L,equal to 0.6 g COD/L)from xylose(10 g/L).The caproate concentration in the batch mode was further increased to 1.6 g/L.However,changing the substrate to ethanol did not promote caproate production,resulting in~1.0 g/L after 45 d of operation.Four genera,Bifidobacterium,Caproiciproducens,Actinomyces,and Clostridium_sensu_stricto_12,were identified as the enriched caproate-producing bacteria.The enzymes in the fatty acid biosynthesis(FAB)pathway for caproate production were identified via metagenomic analysis.The enzymes for the conversion of(C_(n+2))-2,3-Dehydroxyacyl-CoA to(C_(n+2))-Acyl-CoA(i.e.,EC 1.3.1.8 and EC 1.3.1.38)in the reverseβ-oxidation(RBO)pathway were not identified.These results could extend the understanding of low-temperature caproate production.

关 键 词：Xylose fermentation Caproate Low temperature BIFIDOBACTERIUM FAB pathway RBO pathway 

分 类 号：F426[经济管理—产业经济]