摘要
该研究采用传统培养分离法结合透明圈法、淀粉酶活性测定从酱香型白酒大曲中分离、筛选高产淀粉酶的芽孢杆菌(Bacillus sp.)菌株,通过形态学观察及分子生物学技术对筛选菌株进行鉴定,并对其耐酸性进行驯化,同时比较驯化前后菌株所产淀粉酶的酶学性质。结果表明,筛选出一株高产淀粉酶的菌株AmyX8,其被鉴定为枯草芽孢杆菌(Bacillus subtilis)。菌株AmyX8发酵12 h时,淀粉酶活力最高,为570.6 U/mL;该菌株的最适生长pH为7,在pH 1~5的环境下生长困难,其所产淀粉酶在pH 6条件下具有最高活性(549.8 U/mL)。经耐酸性驯化,成功将菌株AmyX8的生长pH驯化至5,得到菌株AmyX8AR,其在发酵24 h时的OD600 nm值是驯化前菌株AmyX8的7.5倍,在发酵27 h时的淀粉酶活(525.8 U/mL)最高,是驯化前菌株AmyX8所产淀粉酶最高酶活的3.2倍;其所产淀粉酶的最适反应温度与驯化前保持一致,仍为40℃,最适反应pH从5下降为4,pH和温度稳定性均得到提高,且在最适反应条件最高活性达到559.6 U/mL。
High amylase-yield Bacillus strains from sauce-flavor(Jiangxiangxing)Baijiu Daqu were isolated and screened by traditional culture separation method combined with transparent circle method and amylase activity measurement.The screened strains were identified through morphological observation and molecular biology technology,their acid resistance was acclimated,and the enzymatic characteristic of the amylase produced by the strains before and after acclimation were also compared.The results showed that a strain AmyX8 with high-yield amylase was screened and identified as Bacillus subtilis,and its amylase activity was highest(570.6 U/ml)after fermentation for 12 h.The optimal growth pH of strain AmyX8 was 7,and it was difficult to grow at pH 1-5.The amylase produced by the strain had the highest activity(549.8 U/ml)at pH 6.After acid resistance acclimation,the culture pH of the strain AmyX8 was successfully acclimated to pH 5,and the strain AmyX8AR was obtained.Its OD600 nm value fermentation for 24 h was 7.5 times that of strain AmyX8 before domestication.The highest amylase activity was 525.8 U/ml after fermentation for 27 h,which was 3.2 times of the highest amylase activity of AmyX8 before acclimation.The optimum reaction temperature of the amylase was consistent with that before acclimation,which was still 40℃,the optimum reaction pH decreased from 5 to 4,the pH and temperature stability was improved,and the highest activity reached 559.6 U/ml under the optimum reaction conditions.
作者
张璋
赵腾飞
李红霞
宋露露
ZHANG Zhang;ZHAO Tengfei;LI Hongxia;SONG Lulu(Department of Brewing Engineering,Moutai Institute,Zunyi 564507,China)
出处
《中国酿造》
CAS
北大核心
2024年第8期74-79,共6页
China Brewing
基金
遵义市科技计划项目(遵市科合HZ字〔2021〕314号)
茅台学院高层次人才科研启动经费项目(mygccrc[2022]003)
贵州省科技计划项目(黔科合基础-ZK[2022]一般543)
茅台学院高层次人才科研启动经费项目(mygccrc[2022]002)
国家自然科学基金地区科学基金项目(32260229)。
关键词
酱香型白酒大曲
淀粉酶
芽孢杆菌
分离
筛选
鉴定
耐酸性驯化
酶学性质
sauce-flavor Baijiu Daqu
amylase
Bacillus
isolation
screening
identification
acid resistance acclimation
enzymatic characteristic
