高产蛋白酶菌株等离子体诱变及其在提高豆粕发酵效果中的应用

采用常压室温等离子体(ARTP)技术对Bacillus amyloliquefaciens 10160进行诱变处理。以致死率达到80%作为ARTP诱变(诱变时间为10 s)的最佳剂量,筛选得到了C5和C12两株遗传稳定的诱变菌株.。与初始菌株相比,诱变菌株的中性蛋白酶酶活分别提高了86.0%和85.0%。十二烷基硫酸钠聚丙烯酰胺凝胶电泳(SDS-PAGE)分析显示,C5、C12以及初始菌株提取的蛋白的组成无明显的差异,然而诱变样品的蛋白浓度明显高于初始菌株。通过豆粕液态发酵发现,与初始菌株相比,菌株C5发酵后的多肽得率和含量分别提高了14.2%和15.6%;菌株C12发酵后的多肽得率和含量分别提高了13.2%和11.8%。诱变后发酵液中中性蛋白酶的酶活也大大提高,菌株C5和C12发酵后中性蛋白酶酶活分别增加了26.0%和29.8%。多肽分子量分布和ACE抑制率无显著差异。可见,ARTP处理Bacillus amyloliquefaciens 10160可以显著提高其豆粕液态发酵制备降血压肽的产率。

High-yield-of-protease Strain Treated by ARTP and Its Improvement of Fermentation of Soybean Meal

Bacillus amyloliquefaciens 10160 was treated by the technology of atmospheric and room temperature plasma (ARTP). Under the optimum dose of of lethality 80% for ARTP-induced mutagenesis (10 s), two stable mutant strains of C5 and C12 were succefully screened. Compared with the original strain, the neutral protease activities of C5 and C12 strains were increased by 86.0% and 85.0%, respectively. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) observations indicated that, the composition of the proteins extracted from C5, C12, and the original strains was similar, while the treated samples exhibited higher protein concentrations. The liquid fermentation experiments of soybean meal showed that, as compared with the original strain, the yield and content of peptides in the fermentation broth of C5 and C12 strains increased by 14.2% and 15.6%, and 13.2% and 11.8%, respectively. Neutral protease activities in the fermentation broths of C5 and C12 strains increased by 26.00% and 29.84%, respectively. There was no significant difference in the molecular weight distribution and ACE inhibition rate between the strains. Therefore, ARTP treatment of Bacillus amyloliquefaciens 10160 can significantly increase the yield of peptides produced by liquid fermentation of soybean meal.