常压室温等离子体诱变选育富硒纳豆芽孢杆菌

纳豆芽孢杆菌可以转化亚硒酸钠为有机硒。对一株纳豆芽孢杆菌的生长曲线进行测定,确定了亚硒酸钠适宜的添加时间和添加量。以纳豆芽孢杆菌BSN424为出发菌株,采用常压室温等离子体诱变系统进行诱变,根据耐硒和富硒能力筛选,经连续传代培养后筛选出了富硒纳豆芽孢杆菌。结果表明,适宜加硒时间为培养后3 h,培养时间为24 h,培养基适宜硒质量浓度为6μg/mL,常压室温等离子体诱变系统功率为100 W,诱变时间为25 s。诱变后筛选得到一株具有较高富硒能力的诱变菌株BN-44,经摇瓶发酵后的富硒量为1136.43μg/g,相比出发菌株的742.12μg/g提高了53.13%。研究表明常压室温等离子体诱变育种能有效地对纳豆芽孢杆菌BSN424进行诱变,旨在为有机硒生物转化法中寻找益生菌富硒载体及其诱变育种提供一定依据。

Screening of Selenium-Enriching Bacillus natto by Atmospheric and Room Temperature Plasma Mutation

Bacillus natto can convert sodium selenite into organic selenium. The growth curve of a strain of Bacillus natto was measured, and the optimum time and addition amounts of sodium selenite were determined. Using B.natto BSN424 as original strain, based on screening of Se-tolerance and Se-enri-ching, a genetic stable mutant strain BN-44 was obtained by atmospheric and room temperature plasma mutagenesis system. The results showed that the optimum time for selenium addition was at the 3 rd hour in the culture period, and then the culture was continued to 24 hours. The optimum mass concentration of selenium in culture medium was 6 μg/mL. The power of atmospheric and room temperature plasma mutagenesis system was 100 W and the mutagenic time was 25 s. After mutagenization, the BN-44 was eventually selected as the best strain with a high selenium content. Compared to the original strain, the selenium content after shaking and fermentation by BN-44 was increased from 742.12 μg/g to 1 136.43 μg/g, which was increased by 53.13%. The results had shown that the atmospheric and room temperature plasma mutagenesis breeding method could mutagenize Bacillus natto BSN424 effectively, which provided a basis for the search of Se-enriching probiotic vector and its mutation breeding in organic selenium biotransformation.