文献类型：期刊文献

英文题名：Phosphoketolase Pathway for Xylose Catabolism in Clostridium acetobutylicum Revealed by ¹³C Metabolic Flux Analysis

作者：Liu, Lixia[1];Zhang, Lei[1];Tang, Wei[1];Gu, Yang[1];Hua, Qiang[2];Yang, Sheng[1];Jiang, Weihong[1];Yang, Chen[1]

机构：[1]Chinese Acad Sci, Shanghai Inst Biol Sci, Inst Plant Physiol & Ecol, Key Lab Synthet Biol, Shanghai, Peoples R China;[2]E China Univ Sci & Technol, State Key Lab Bioreactor Engn, Shanghai 200237, Peoples R China

年份：2012

卷号：194

期号：19

起止页码：5413

外文期刊名：JOURNAL OF BACTERIOLOGY

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000308749700027)】；

基金：This work was supported in part by the Natural Science Foundation of China (31070033 and 31121001), the National Basic Research Program of China (973: 2012CB721101), the Knowledge Innovation Program of the Chinese Academy of Sciences (KSCX2-EW-G-5 and KSCX1-YW-11C3), and the Open Funding Project of the State Key Laboratory of Bioreactor Engineering.

语种：英文

摘要：Solvent-producing clostridia are capable of utilizing pentose sugars, including xylose and arabinose; however, little is known about how pentose sugars are catabolized through the metabolic pathways in clostridia. In this study, we identified the xylose catabolic pathways and quantified their fluxes in Clostridium acetobutylicum based on [1-C-13] xylose labeling experiments. The phosphoketolase pathway was found to be active, which contributed up to 40% of the xylose catabolic flux in C. acetobutylicum. The split ratio of the phosphoketolase pathway to the pentose phosphate pathway was markedly increased when the xylose concentration in the culture medium was increased from 10 to 20 g liter(-1). To our knowledge, this is the first time that the in vivo activity of the phosphoketolase pathway in clostridia has been revealed. A phosphoketolase from C. acetobutylicum was purified and characterized, and its activity with xylulose-5-P was verified. The phosphoketolase was overexpressed in C. acetobutylicum, which resulted in slightly increased xylose consumption rates during the exponential growth phase and a high level of acetate accumulation.