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 Aspergillus oryzae 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.

大气和室温血浆（ARTP）系统是一种用于微生物育种的新型高效诱变方案。在这项研究中，ARTP被用来治疗孢子的孢子米曲霉菌株3.042，用于选择高酸性蛋白酶的生产者。以150秒的照射时间和90％的致死率，首先基于不同的突变菌落形态和蛋白酶活性的澄清晕圈与菌落直径的比率来选择具有较高酸性蛋白酶活性的19个突变体。酸性蛋白酶活性的测量结果表明，突变株B-2具有稳定的遗传稳定性，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％ 。总之，在酱油发酵的中后期，鉴定出的突变菌株B-2具有极大的增强酸性蛋白酶活性的潜力。