豆豉来源的纤溶酶产生菌株的筛选及发酵性能研究

Research on Screening and Fermentation Properties of Fibrinolysin Producing Strains from Fermented Soya Beans

采用酪蛋白平板初筛的方法,从豆豉中分离到278株具有蛋白酶活力的菌株,经过纤维蛋白培养平板复筛,并获得1株产纤溶酶能力较强的菌株,命名为LZ-238。在对LZ-238菌株常规形态学及生理生化特性鉴定的基础上,对部分长度的16SrDNA同源性进行了分析,发现LZ-238菌株与地衣芽孢杆菌相似度达99.5%,命名为Bacillus amyloliquefaciens LZ-238。通过液体发酵及阿胶纳豆的制作,对LZ-238菌株产酶及应用性能进行了评价。经发酵,LZ-238菌株纤溶酶的最高产量可达28.12U/mL,其制作的阿胶纳豆具有豆豉的特有香气且几乎无氨味,更符合中国人的口味。

Two hundred and seventy-eight strains of protease-producing strains are isolated from traditional Chinese fermented soybean food by using casein-plate method and one strain of highest fibrinolytic enzyme producing strains is screened by fibrin-plate method, which is named as LZ-238. Based on morphology, physiological and biochemical characteristics, LZ-238 is identified by 16S rDNA sequences and systematic analysis. The results indicate that 16S rDNA sequences of LZ-238 have 99. 5% similarity to the partial sequence of Bacillus licheniformis, suggesting that LZ-238 is categorized as B. licheniforrnis, and denominated as B. licheniformis LZ-238. The fermentation performance of LZ-238 under shaking and donkey-hide glue natto production is inspected preliminarily. Fibrinolytic enzyme activity of B. licheniformis LZ-238 reaches 28. 19 U/mL. The donkey-hide glue natto produced by B. licheniforrnis LZ-238 has less ammonia smell and is more in line with Chinese taste.