[目的]筛选L-缬氨酸高产菌株并研究其发酵条件.[方法]以黄色短杆菌(Brebvibacterium flavum)突变株ZGH61.28为出发菌株,采用紫外线(UV)、硫酸二乙酯(DES)和亚硝基胍(NTG)3种诱变剂进行诱变处理,通过摇瓶培养筛选出L-缬氨酸高产突变菌株.[结果]经过UV、DES和NTG3种诱变剂处理菌株ZGH6128,逐步获得菌株JVHK597,并具有Leu营养缺陷、Ile营养缺陷、Met营养缺陷、α-AB抗性、2-TA抗性5种遗传标记.在未优化的条件下,菌株JVHK597摇瓶发酵72 h的产酸量达41.2 g/L.8次传代试验结果表明,菌株JVHK597的产酸能力稳定,经鉴定,菌株JVHK597的基因型为(Leu-,Ile-,Met-,α-ABr,2 -TAr),遗传标记具有稳定性.发酵培养基中硫酸镁( MgSO4·7H2O)和磷酸二氢钾的含量分别为0.6和1.4 g/L时,最有利于菌株生产L-缬氨酸.[结论]试验筛选出了L-缬氨酸高产菌株JVHK597,并为其发酵培养提供了指导.%[Objective]The aim was to screen superior strain of L-valine and study its fermentation condition. [ Method] With the mutant strain ZGH6128 of Brebvibacterium flavum as initial strain, 3 kinds of mutagens of ultraviolet (UV), diethyl sulfate (DES) and nitrosoguani-dine (NTG) were used in its mutagene treatments, its superior mutant strain of L-valine was screened out through shaking culture. [ Result] The strain ZGH6128 was treated with 3 kinds of mutagens of UV, DES and NTG and the mutant strain JVHK597 was obtained progressively. This mutant strain possessed 5 genetic marks of Leu auxotroph, Ile auxotroph, Met auxotroph, a-AB resistance and 2-TA resistance. Under non-optimized condition, the production of acid from the strain JVHK597 reached 41.2 g/L after fermentation for 72 h. The experimental results of 8 passages showed that the acid producing ability of the strain JVHK597 was stable and its genotype was identified to be (Leu-, Ile-, Met-, α-AB', 2-TA') and its genetic marks had stability. When the contents of bitter salt (MgSO4 · 7H2O) and monopotassium phosphate in fermentation medium were 0.6 and 1.4 g/L resp. , it was most beneficial for the strain to produce L-valine. [Conclusion]The superior strain JVHK597 of L-valine was screened out in this experiment and it provided guidance for its fermentation culture.
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