透明质酸产生菌的紫外诱变及发酵工艺的优化

UV mutagenesis and fermentation optimization of hyaluronic acid-producing strain

利用安全的(generally recognized as safe,GRAS)菌株发酵生产透明质酸(hyaluronic acid,HA)已成为发酵法生产透明质酸的研究热点。该研究以GRAS菌株贝莱斯芽孢杆菌(Bacillus velezensis)Z1为出发菌株,经过紫外诱变后,得到1株高产HA且稳定性良好、透明质酸酶阴性的突变株ZV1。然后在单因素试验的基础上,采用Box-Behnken中心组合设计并进行响应面法分析,得到突变株ZV1最优发酵培养基成分:葡萄糖69.5 g/L,胰蛋白胨10.2 g/L,牛肉浸膏14.8 g/L,MgSO 4·7H 2O 1.5 g/L;再利用正交试验优化得到该菌株最佳发酵条件:pH值7.0,摇床转速150 r/min,温度35℃,装液量140 mL。在优化后的培养基成分与发酵条件下,突变株ZV1的HA产量最大可达到1.169 g/L,较出发菌株Z1提高了51.03%。因此,经过紫外诱变与发酵工艺的优化后,B.velezensis Z1的HA产量得到有效提高,研究结果对工业化发酵生产HA具有应用价值。

Hyaluronic acid(HA)production through fermentation using GRAS strains has become a research hotspot.This study aimed to improve the HA yield of a GRAS HA-producing strain,Bacillus velezensis Z1,by UV mutagenesis and fermentation process optimization.After UV mutagenesis,mutant strain ZV1 was obtained with high HA yield,good stability,and negative hyaluronidase.Based on the single factor experiment,the fermentation medium composition was optimized with the Box-Behnken design and response surface analysis.The data indicated that the optimal medium compositions were glucose 69.5 g/L,tryptone 10.2 g/L,beef extract 14.8 g/L,and MgSO 4·7H 2 O 1.5 g/L.The fermentation conditions were further optimized by single factor experiment and orthogonal test design,and the optimal fermentation conditions were as follows:pH 7.0,shaking speed 150 r/min,temperature 35℃,medium volume 140 mL.Under the optimal medium and fermentation conditions,the maximum HA yield of the mutant strain ZV1 reached 1.169 g/L,which was increased by 51.03%compared with that of the original strain Z1.Therefore,the HA yield of Bacillus velezensis Z1 was effectively improved by UV mutagenesis and optimization of fermentation process,which has a certain application value for the production of HA by industrial fermentation.