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

ABSTRACT

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.