偏高温大曲发酵过程中B.licheniformis和B.subtilis动态变化和生产特性

Dynamic Change and Production Characteristics of B. licheniformis and B. subtilis during Fermentation of High-temperature Daqu

对偏高温大曲发酵过程中Bacillus licheniformis和Bacillus subtilis主要酶活及对部分理化因子耐受性进行分析。31株供试菌中,能够在65℃、体积分数7%乙醇和3.8mmol/mL酸度条件下生长的菌株分别为77.4%、83.9%、71.0%;能够产淀粉酶、脂肪酶、蛋白质酶的菌株分别占87.1%、96.8%、90.3%,其中高产菌株分别占48.4%、35.5%、38.7%;所有菌株在生理生化特征、耐受性和产酶能力上均不完全相同,表明该2个种的菌株在偏高大曲发酵过程中呈现种间多态性和生长代谢的复杂性。

In the fermentation process of slightly high temperature Daqu, the key enzyme activities of 31 strains belonging to Bacillus licheniformis and Bacillus subtilis and their tolerance to several physical and chemical factors were analyzed. Of these strains, 77.4% could grow at 65 ℃, 83.9% in 7% ethanol and 71.0% at acidity of 3.8 mmol/mL, respectively. In addition, 87.1%, 96.8% and 90.3% of them were capable of producing amylase, lipase and protease, respectively, and the proportions of high-yield strains were 48.4%, 35.5% and 38.7%, respectively. All 31 strains totally differed in physiological and biochemical characteristics, tolerance and enzyme-producing ability, showing intraspecific diversity and metabolic complexity of both Bacillus species during the initial fermentation process.