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[1,3,5]; 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] State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; [2] University of Chinese Academy of Sciences, Beijing, China; [3] Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China; [4] State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China; [5] University of Massachusetts, Amherst, MA, United States

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：EI(收录号：20131716230784)

语种：英文

外文关键词：Biochemistry - Reinforced plastics - Coenzymes - Genes - Monomers

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 13C positional enrichment in 3HV. Notably, 13C 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 ΔphaEC 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. ? 2013, American Society for Microbiology.