复合诱变选育5-ALA高产菌株及发酵条件优化

Breeding of High-Yield 5-ALA Strain by Compound Mutation and Fermentation Condition Optimization

以类球红细菌(Rhodobacter sphaeroides)为出发菌株,通过紫外-氯化锂复合诱变,筛选出高产5-ALA的菌株,并通过单因素试验对其发酵产5-ALA条件进行优化。结果表明,在紫外照射80 s、氯化锂浓度0.6%的最适诱变条件下,突变菌落形态大小与产5-ALA能力呈正相关,单菌落直径越大,产5-ALA能力越强,筛选出1株高产5-ALA菌株H80110,其5-ALA产量达24.56 mg/L,较初发菌株提高97.14%。其最佳发酵条件为初始pH 6.6、接种量20%、装液量100 mL/250 mL,且发酵周期缩短为3 d,该菌株具有良好的遗传稳定性。

Using Rhodobacter sphaeroides as the starting strain,high 5-ALA producing strains were screened through UV lithium chloride composite mutagenesis,and the fermentation condition for 5-ALA production was optimized through single factor experiments.The results showed that the optimal mutation condition was ultraviolet irradiation for 80 s and lithium chloride concentration of 0.6%.The size of mutant colony morphology was positively correlated with the ability to produce 5-ALA.The larger the diameter of a single colony,the stronger the ability to produce 5-ALA.One high-yield 5-ALA strain H80110 was screened out,with a 5-ALA yield of 24.56 mg/L,which was 97.14%higher than the original strain.The optimal fermentation conditions were initial pH 6.6,inoculation volume 20%,liquid loading volume 100 mL/250 mL,and fermentation cycle was shortened to 3 days.The strain had good genetic stability.