文献类型：期刊文献

英文题名：Multiple Propionyl Coenzyme A-Supplying Pathways for Production of the Bioplastic Poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate) in Haloferax mediterranei

作者：Han, Jing[1];Hou, Jing[1,2];Zhang, Fan[1,3];Ai, Guomin[1];Li, Ming[1,2];Cai, Shuangfeng[1,2];Liu, Hailong[1,2];Wang, Lei[1];Wang, Zejian[4];Zhang, Siliang[4];Cai, Lei[1,2];Zhao, Dahe[1,2];Zhou, Jian[1];Xiang, Hua[1]

机构：[1]Chinese Acad Sci, Inst Microbiol, State Key Lab Microbial Resources, Beijing, Peoples R China;[2]Univ Chinese Acad Sci, Beijing, Peoples R China;[3]Chinese Acad Sci, Beijing Inst Genom, Beijing, Peoples R China;[4]E China Univ Sci & Technol, State Key Lab Bioreactor Engn, Shanghai 200237, Peoples R China

年份：2013

卷号：79

期号：9

起止页码：2922

外文期刊名：APPLIED AND ENVIRONMENTAL MICROBIOLOGY

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000317474800009)】；

基金：This study was supported by grants from the National 863 Program of China (2010AA09Z401), the National Natural Science Foundation of China (30830004, 30925001, and 31000023), and the Chinese Academy of Sciences (KSCX2-EW-G-2-4).

语种：英文

摘要：Haloferax mediterranei is able to accumulate the bioplastic poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) with more than 10 mol% 3-hydroxyvalerate (3HV) from unrelated carbon sources. However, the pathways that produce propionyl coenzyme A (propionyl-CoA), an important precursor of 3HV monomer, have not yet been determined. Bioinformatic analysis of H. mediterranei genome indicated that this strain uses multiple pathways for propionyl-CoA biosynthesis, including the citramalate/2-oxobutyrate pathway, the aspartate/2-oxobutyrate pathway, the methylmalonyl-CoA pathway, and a novel 3-hydroxypropionate pathway. Cofeeding of pathway intermediates and inactivating pathway-specific genes supported that these four pathways were indeed involved in the biosynthesis of 3HV monomer. The novel 3-hydroxypropionate pathway that couples CO2 assimilation with PHBV biosynthesis was further confirmed by analysis of C-13 positional enrichment in 3HV. Notably, C-13 metabolic flux analysis showed that the citramalate/2-oxobutyrate pathway (53.0% flux) and the 3-hydroxypropionate pathway (30.6% flux) were the two main generators of propionyl-CoA from glucose. In addition, genetic perturbation on the transcriptome of the Delta phaEC mutant (deficient in PHBV accumulation) revealed that a considerable number of genes in the four propionyl-CoA synthetic pathways were significantly downregulated. We determined for the first time four propionyl-CoA-supplying pathways for PHBV production in haloarchaea, particularly including a new 3-hydroxypropionate pathway. These results would provide novel strategies for the production of PHBV with controllable 3HV molar fraction.