L-缬氨酸产生菌的原生质体融合及抗高糖融合株的筛选

Protoplast Fusion of L-Valine Producer and Screening of Fusants by Improving High-Glucose Tolerance

通过原生质体融合技术选育出一株抗高糖的融合株。以黄色短杆菌(Brevibacterium flavum)NV128和黄色短杆菌(B.flavum)JV16(Leu-Ile-Met-)为亲本菌株,通过单灭活原生质体融合、高糖梯度平板筛选及进一步的硫酸二乙酯(DES)诱变,获得了一株L-缬氨酸高产菌NJ-237。同时研究了影响原生质体形成、再生的3种重要条件(青霉素、酶和渗透压稳定剂),并确定了其最佳处理浓度和时间。该融合株经7 L发酵罐培养72 h L-缬氨酸达到46.8 g/L,糖酸转化率为27.7%,比两亲株都有显著提高。

A fusant which could be resistant to high concentration of glucose was screened by fusing protoplasts in this study.The L-valine overproducing fusant was derived from Brevibacterium flavum NV128 and JV16（Leu-Ile-Met-）,and was screened on high-glucose gradient plates by means of fusing the single inactivated protoplasts and diethylsulfate（DES） treatment.At the same time,three different conditions（penicillin,lysozyme and osmotic stabilizer）affecting the formation and regeneration of protoplasts were studied and the optimum conditions were determined.Under the optimum conditions,the titer of L-valine achieved at 46.8g/L after 72h culture,and the yield of L-valine on glucose was 27.7%.