淡豆豉炮制过程中产纤溶酶微生物的筛选和鉴定

Screening and identification of fibrinolytic enzyme-producing microbes in fermentation process of Sojae Semen Praeparatum

目的筛选和鉴定淡豆豉炮制过程中产纤溶酶的优势菌株。方法按《中国药典》2020年版制备淡豆豉;采用酪蛋白平板法和纤维蛋白平板法分别对淡豆豉炮制不同时间点样本中产纤溶酶的微生物进行初筛和复筛;将产纤溶酶微生物分别接种在特定的液体培养基中培养,获得纯种发酵液,用纤维蛋白平板法测定发酵液的纤溶酶活力;应用16S rDNA和18S rDNA通用引物分别对产纤溶酶细菌和真菌进行PCR扩增、对扩增产物进行测序,测序结果通过NCBI同源性比对、MEGA4.1软件构建系统发育树进行分子生物学鉴定。结果筛选获得3种产纤溶酶细菌,分别为枯草芽孢杆菌Bacillussubtilis、嗜麦芽窄食单胞菌Stenotrophomonas maltophilia、微球菌Micrococcus。纤维蛋白平板法测定纯种发酵液纤溶酶活力的结果显示,嗜麦芽窄食单胞菌所产纤溶酶活力最高,达527.49 IU/mL。结论淡豆豉炮制过程中存在高产纤溶酶的优势菌株,淡豆豉的溶栓作用值得进一步研究。为揭示淡豆豉炮制中纤溶酶形成机制奠定基础。

Objective To screen and identify the dominant strains which produce fibrinolytic enzyme during the processing of Sojae Semen Praeparatum(SSP, Dandouchi in Chinese). Methods SSP was prepared according to the Chinese Pharmacopoeia(2020 edition), and samples were taken at different time points during the fermenting process of SSP.The casein plate method and fibrin plate method were used to screen the fibrinolytic enzyme-producing microorganisms in samples at different time points. The fibrinolytic enzyme-producing microorganisms were inoculated in the designated liquid medium to obtain single strain fermentation broth, and fibrin plate method was used to measure the fibrinolytic activity of the fermentation broth. The DNA sequences of fibrinolytic enzyme-producing bacteria and fungi were amplified using 16S rDNA and 18S rDNA universal primer by PCR respectively.The amplified products were sequenced, and the sequencing results were identified through NCBI homology comparison. Molecular biological identification was done by phylogenetic tree constructed by MEGA 4.1 software. Results Three types of fibrinolytic enzyme-producing bacteria were screened out and identified in this study. They were Bacillus subtilis, Stenotrophomonas maltophilia and Micrococcus, respectively. The result of fibrin plate method showed that the fermentation broth of S. maltophilia had the highest fibrinolytic activity, reaching 527.49 IU/mL. Conclusion There are fibrinolytic enzyme-producing dominant microorganisms existing in the fermenting process of SSP and the thrombolytic effect of SSP is worthy of further study. This study lays the foundation for revealing the formation mechanism of fibrinolytic enzyme in the fermentation process of SSP.