L-缬氨酸高产菌诱变育种的研究

Studies on the Breeding of L-Valine Hyper-Producing Mutant

摘要:

以黄色短杆菌(Brevibacterium flavum)L-缬氨酸产生菌XQ-2为出发菌株,经硫酸二乙酯(DES)和亚硝基胍(NTG)逐级诱变处理,氨基酸结构类似物α-氨基丁酸(-αAB)、2-噻唑丙氨酸(2-TA)和α-氨基-β-羟基戊酸(AHV)定向筛选,获得一株L-缬氨酸高产菌XQ-8(Leul(-ABhr2-TAhrAHVhr)。在以135 g/L葡萄糖为碳源和50 g/L硫酸铵为氮源的培养基中摇瓶发酵72 h,产酸达64~66 g/L。

Abstract:

Using Brevibacterium flavum XQ-2(Leul(-ABrAHVr2-TAr) as a starting strain for stepwise mutagenesis by diethylsulfate(DES),N-methyl-N’-nitro-soguanidine(NTG) treatment,a L-valine hyper-producing mutant XQ-8(Leul(-AB hr2-TAhr AHVhr) was obtained,which could be resistant to high concentration α-amino-butyric acid(α-AB),2-thiazole-DL-alanaine(2-TA) and α-amino-β-hydroxy-valeric acid(AHV).As a result,high L-valine concentration(64~66g/L) was obtained with shaking at 31±1℃ for 72h in the medium containing 135g/L glucose and 50g/L(NH4)2SO4.