Key Laboratory of Agricultural and Animal Products Storation & Processing of Guizhou Province (ORCID: https://orcid.org/0000-0002-3523-0872 [L.H.]).
College of Liquor and Food Engineering, Guizhou University, Guiyang 550025, People's Republic of China.
J Food Prot. 2021 Apr 1;84(4):717-727. doi: 10.4315/JFP-20-307.
Fibrinolytic enzymes are effective and highly safe in treating cardiovascular and cerebrovascular diseases. Therefore, screening fibrinolytic enzyme-producing microbial strains with excellent fermentation performance is of great value to industrial applications. The fibrin plate method was used in screening strains with high yields of fibrinolytic enzymes from different fermented food products, and the screened strains were preliminarily identified using molecular biology. Then, the strains were used for solid-state fermentation of soybeans. Moreover, the fermentation product douchi was subjected to fibrinolytic activity measurement, sensory evaluation, and biogenic amine content determination. The fermentation performance of each strain was comprehensively evaluated through principal component analysis. Finally, the target strain was identified based on strain morphology, physiological and biochemical characteristics, 16S rDNA sequence, and phylogenetic analysis results. A total of 15 Bacillus species with high fibrinolysin activity were selected. Their fibrinolytic enzyme-producing activity levels were higher than 5,500 IU/g. Through molecular biology analysis, we found 4 strains of Bacillus subtilis, 10 strains of Bacillus amyloliquefaciens, and 1 strain of Bacillus velezensis. The principal component analysis results showed that SN-14 had the best fermentation performance and reduced the accumulation of histamine and total amine, the fibrinolytic activity of fermented douchi reached 5,920.5 ± 107.7 IU/g, and the sensory score was 4.6 ± 0.3 (out of 5 points). Finally, the combined results of physiological and biochemical analyses showed SN-14 was Bacillus velezensis. The high-yield fibrinolytic and excellent fermentation performance strain Bacillus velezensis SN-14 has potential industrial application.
纤溶酶在治疗心脑血管疾病方面具有高效、高安全性的特点。因此，筛选具有优良发酵性能的产纤溶酶微生物菌株对于工业应用具有重要意义。本研究采用纤维蛋白平板法从不同发酵食品中筛选产纤溶酶活力高的菌株，并采用分子生物学手段对筛选得到的菌株进行初步鉴定，然后利用固态发酵法对大豆进行发酵，再对发酵得到的腐乳进行纤溶活力测定、感官评价和生物胺含量测定，最后通过主成分分析对各菌株的发酵性能进行综合评价，并基于菌株形态、生理生化特性、16S rDNA 序列和系统发育分析结果对目标菌株进行鉴定。共筛选得到 15 株具有较高纤溶酶活力的芽孢杆菌，其纤溶酶活力均高于 5,500 IU/g。通过分子生物学分析，发现其中 4 株为枯草芽孢杆菌，10 株为解淀粉芽孢杆菌，1 株为韦荣氏球菌。主成分分析结果表明，SN-14 的发酵性能最佳，且能降低腐乳中组胺和总胺的积累，发酵得到的腐乳的纤溶活力达到 5,920.5±107.7 IU/g，感官评分为 4.6±0.3（满分 5 分）。最终，综合生理生化分析结果，鉴定 SN-14 为韦荣氏球菌。筛选得到的高产纤溶酶活力且发酵性能优良的菌株韦荣氏球菌 SN-14 具有潜在的工业应用价值。
