Enhancement of precursor amino acid supplies for improving bacitracin production by activation of branched chain amino acid transporter BrnQ and deletion of its regulator gene lrp in Bacillus licheniformis  

作　　者：Jiang Zhu Dongbo Cai Haixia Xu Ziwei Liu Bowen Zhang Fei Wu Junhui Li Shouwen Chen 

机构地区：[1]Environmental Microbial Technology Center of Hubei Province,Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources,State Key Laboratory of Biocatalysis and Enzyme Engineering,College of Life Sciences,Hubei University,Wuhan,430062,PR China [2]Lifecome Biochemistry Co.Ltd,Nanping,353400,PR China

出　　处：《Synthetic and Systems Biotechnology》2018年第4期236-243,共8页合成和系统生物技术（英文）

基　　金：the National Program on Key Basic Research Project(973 Program,No.2015CB150505);the Technical Innovation Special Fund of Hubei Province(2018ACA149);The Key Technology Project of China National Tobacco Corporation(110201502014).

摘　　要：Bacitracin,a new type of cyclic peptide antibiotic,is widely used as the feed additive in feed industry.Branched chain amino acids(BCAAs)are the key precursors for bacitracin synthesis.In this research,soybean meal was served as the raw material to supply precursor amino acids for bacitracin synthesis,and enhanced production of bacitracin was attempted by engineering BCAA transporter BrnQ and its regulator Lrp in the bacitracin industrial production strain Bacillus licheniformis DW2.Firstly,our results confirmed that Lrp negatively affected bacitracin synthesis in DW2,and deletion of lrp improved intracellular BCAA accumulations,as well as the expression level of BCAA transporter BrnQ,which further led to a 14.71%increase of bacitracin yield,compared with that of DW2.On the contrary,overexpression of Lrp decreased bacitracin yield by 12.28%.Secondly,it was suggested that BrnQ acted as a BCAA importer in DW2,and overexpression of BrnQ enhanced the intracellular BCAA accumulations and 10.43%of bacitracin yield.While,the bacitracin yield decreased by 18.27%in the brnQ deletion strain DW2△brnQ.Finally,BrnQ was further overexpressed in lrp deletion strain DW2△lrp,and bacitracin yield produced by the final strain DW2△lrp::BrnQ was 965.34 U/mL,increased by 22.42%compared with that of DW2(788.48 U/mL).Collectively,this research confirmed that Lrp affected bacitracin synthesis via regulating the expression of BCAA transporter BrnQ and BCAA distributions,and provided a promising strain for industrial production of bacitracin.

关 键 词：Bacillus licheniformis BACITRACIN Regulator Lrp BCAA transporter BrnQ Branched chain amino acid 

分 类 号：R73[医药卫生—肿瘤]