rhtB基因过表达苏氨酸工程菌发酵过程的优化控制  

Optimization of Culture Conditions of rhtB Gene Overexpressed Threonine-producing Strain

作　　者：孔晶[1] 贾建波[1] 赵玉萍[1] 任世英[1] 

机构地区：[1]淮阴工学院生命科学与化学工程学院,江苏淮安223003

出　　处：《安徽农业科学》2011年第34期20951-20952,共2页Journal of Anhui Agricultural Sciences

基　　金：淮安市科技支撑计划(农业)项目(SN1049)

摘　　要：[目的]构建了负责运输苏氨酸至胞外的转运蛋白的关键基因rhtB过表达的苏氨酸发酵菌M122,考察不同的碳源、氮源及pH对该重组菌产L-苏氨酸的影响。[方法]选用不同的碳、氮源对L-苏氨酸生产菌株的发酵过程进行分析,对发酵培养基的碳、氮源及pH进行优化。[结果]定向改造后苏氨酸发酵菌对营养物质的利用效率增加,使用蔗糖作为碳源发酵时,摇床培养L-苏氨酸产量为28.1 g/L;以(NH4)2SO4或酵母粉作为氮源发酵时,L-苏氨酸产量分别为27.8和28.2 g/L,均优于使用其他氮源时苏氨酸的产量。对发酵的最适pH研究表明,中性条件下更有利于菌体的生长和L-苏氨酸的产生。[结论]确定了苏氨酸发酵菌M122的最佳碳源为蔗糖,最佳氮源为(NH4)2SO4或酵母粉,最适pH为7.0。[Objective] The aim was to construct key gene rhtB overexpressed threonine-producing E.coli strains which transported threonine to extracellular translocator,and to investigate the effect of different carbon and nitrogen sources and pH value on L-threonine.[Method] The fermentation process of different carbon and nitrogen sources on L-threonine yield strains were analyzed to optimize carbon and nitrogen sources of fermentation medium and pH.[Result] Data showed that the suitable carbon source for threonine production by E.coli M122 was sucrose whose yield of threonine was 28.1 g/L.When ammonium sulfate or yeast extract were acted as nitrogen sources,production reached 27.8 and 28.2 g/L,respectively.The yield of threonine was pH dependent and occurred at approximately pH 7.0.[Conclusion] The best carbon source for threonine production by E.coli M122 was sucrose.Either of sources including ammonium sulfate or yeast extract could be used as optimal nitrogen.pH is a critical factor in threonine production,which should be set at 7.0.

关 键 词：L-苏氨酸 发酵 碳源 氮源 

分 类 号：S188.4[农业科学—农业基础科学]