文献类型：期刊文献

英文题名：Optimization of l-methionine feeding strategy for improving S-adenosyl-l-methionine production by methionine adenosyltransferase overexpressed Pichia pastoris

作者：Hu, Hui[1];Qian, Jiangchao[1];Chu, Ju[1];Wang, Yonghong[1];Zhuang, Yingping[1];Zhang, Siliang[1]

机构：[1]E China Univ Sci & Technol, State Key Lab Bioreactor Engn, Natl Engn Res Ctr Biotechnol, Shanghai 200237, Peoples R China

年份：2009

卷号：83

期号：6

起止页码：1105

外文期刊名：APPLIED MICROBIOLOGY AND BIOTECHNOLOGY

收录：;EI(收录号：20093012221151);WOS:【SCI-EXPANDED(收录号:WOS:000267679900013)】；

基金：We are grateful to the National Basic Research Program (973 program no. 2007CB714306), the National High-Technology Research and Development Program (863 Program 2007AA100601), and the Science and Technology Commission of Shanghai Municipality (07pj14027) for their financial supports to this research.

语种：英文

外文关键词：S-adenosyl-L-methionine; Methionine adenosyltransferase; L-methionine; Pichia pastoris; ATP

摘要：The recombinant Pichia pastoris harboring an improved methionine adenosyltransferase (MAT) shuffled gene was employed to biosynthesize S-adenosyl-l-methionine (SAM). Two l-methionine (l-Met) addition strategies were used to supply the precursor: the batch addition strategy (l-Met was added separately at three time points) and the continuous feeding strategies (l-Met was fed continuously at the rate of 0.1, 0.2, and 0.5 g l(-1) h(-1), respectively). SAM accumulation, l-Met conversion rate, and SAM productivity with the continuous feeding strategies were all improved over the batch addition strategy, which reached 8.46 +/- 0.31 g l(-1), 41.7 +/- 1.4%, and 0.18 +/- 0.01 g l(-1) h(-1) with the best continuous feeding strategy (0.2 g l(-1) h(-1)), respectively. The bottleneck for SAM production with the low l-Met feeding rate (0.1 g L-1 h(-1)) was the insufficient l-Met supply. The analysis of the key enzyme activities indicated that the tricarboxylic acid cycle and glycolytic pathway were reduced with the increasing l-Met feeding rate, which decreased the adenosine triphosphate (ATP) synthesis. The MAT activity also decreased as the l-Met feeding rate rose. The reduced ATP synthesis and MAT activity were probably the reason for the low SAM accumulation when the l-Met feeding rate reached 0.5 g l(-1) h(-1).