浓香型白酒大曲中产阿魏酸酯酶菌株的筛选及发酵优化

Screening and Fermentation Optimization of a Ferulic Acid Esterase⁃Producing Strain in Luzhou⁃Flavor Liquor Daqu

为提高在白酒酿造过程中阿魏酸(ferulic acid,FA)的含量,该研究从浓香型白酒大曲中筛选到一株耐高温产阿魏酸酯酶(ferulic acid esterase,FAE)的菌株,经过形态学、生理生化特征和分子生物学鉴定为假单胞菌(Pseudomonas)。通过对pH值、温度、碳源、氮源、诱导物5个发酵条件进行单因素试验和对3个主要影响因子进行响应面试验设计,对该菌株进行液态发酵培养基优化,结果表明该菌株产阿魏酸酯酶优化培养基配方为葡萄糖浓度30 g/L、酵母提取物添加量60 g/L、粉碎的麦麸添加量30 g/L、KCl 0.05 g/L、MgSO_(4)·7H_(2)O 0.05 g/L、K_(2)HPO_(4)0.10 g/L,pH6.0。在此优化培养基条件下该菌株摇瓶发酵的最大酶活力可达73.5 U/L,与优化前得到的酶活力25.5 U/L相比,提升约3倍。

A strain with strong ferulic acid esterase(FAE)activity and thermostability was screened out from the Luzhou⁃flavor liquor Daqu to increase the content of ferulic acid(FA)in the brewing process of liquor.It was identified as Pseudomonas based on morphological,physiological,and biochemical characteristics and molecular sequence.Five fermentation conditions including pH,temperature,carbon source,nitrogen source,and inducer were examined by single factor tests and the top three influencing factors of the liquid fer⁃mentation were optimized by response surface design.The results showed that the optimized medium formula for FAE production of the strain was as follows:glucose 30 g/L,yeast extract 60 g/L,crushed wheat bran 30 g/L,KCl 0.05 g/L,MgSO_(4)·7H_(2)O 0.05 g/L,K_(2)HPO_(4)0.10 g/L,and pH6.0.In the optimized medium,the maximum FAEactivityofthestrainreached 73.5U/L in shake flask fermentation,which was about 3 times of that(25.5U/L)before optimization.