Shu Liang, Si Xiaoguang, Yang Xinda, Ma Wenyan, Sun Jinglan, Zhang Jian, Xue Xianli, Wang Depei, Gao Qiang
Key Laboratory of Industrial Microbiology and Engineering Research Center of Food Biotechnology, Ministry of Education, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China.
The Institute of Seawater Desalination and Multipurpose Utilization, Ministry of Natural Resources, Tianjin, China.
Front Microbiol. 2020 Jun 26;11:1418. doi: 10.3389/fmicb.2020.01418. eCollection 2020.
Atmospheric and room temperature plasma (ARTP) system is a novel and efficient mutagenesis protocol for microbial breeding. In this study, ARTP was employed to treat spores of strain 3.042 for selection of high acid protease producers. With an irradiation time of 150 s at the lethal rate of 90%, 19 mutants with higher acid protease activity were initially selected based on different mutant colony morphology and ratio of the clarification halo of protease activity to the colony diameter. Measurements of the acid protease activity revealed that mutant strain B-2 is characterized by a steady hereditary stability with increased acid protease, neutral protease and total protease activities of 54.7, 17.3, and 8.5%, respectively, and decreased alkaline protease activity of 8.1%. In summary, the identified mutant strain B-2 exhibits great potential for the enhancement of the insufficient acid protease activity during the middle and later stages of soy sauce fermentation.
常压室温等离子体（ARTP）系统是一种用于微生物育种的新型高效诱变方案。在本研究中，采用ARTP处理3.042菌株的孢子，以筛选高酸性蛋白酶产生菌。在致死率为90%的条件下照射150 s，基于不同的突变菌落形态以及蛋白酶活性澄清圈与菌落直径的比例，初步筛选出19株具有较高酸性蛋白酶活性的突变体。酸性蛋白酶活性测定结果表明，突变菌株B-2具有稳定的遗传稳定性，其酸性蛋白酶、中性蛋白酶和总蛋白酶活性分别提高了54.7%、17.3%和8.5%，碱性蛋白酶活性降低了8.1%。综上所述，鉴定出的突变菌株B-2在提高酱油发酵中后期酸性蛋白酶活性不足方面具有巨大潜力。
