Study on the Efficient Isolation and Anti-bacterial Activity of Bacillus Subtilis Micro-vesicles

ZHENG Lixue; KANG Qiuyan; LOU Jingyi; FENG Jinghan; FAN Zongqiang; WANG Shuo; CHEN Fang

doi:10.19728/j.issn1672-6634.2024020003

Abstract：To establish an efficient isolation method of Bacillus subtilis Microvesicles(MVs)and evaluate the antibacterial and anti-inflammatory activities of B.subtilis microvesicles(BS-MVs).Methods:The yield of BS-MVs was increased by screening B.subtilis 2-1 and B.subtilis 579 strains in medium and cul-ture conditions.BS-MVs was purified by ultra-fast centrifugation and density gradient centrifugation,and the in vitro antibacterial activity of BS-MVs was detected by filter paper diffusion method,and better anti-bacterial activity was screened.The anti-inflammatory activity of BS-MVs was studied by establishing a DSS induced ulcerative colitis model.Results:LB medium with 0.5％glucose was selected as the medium for high yield of BS-MVs.The culture time was 24 h,and the separation efficiency of BS-MVs was in-creased.The antibacterial activity of BS2-1-MVs and BS579-MVs with 1 × 1010 particle number/mL were 135％and 99.2％against Candida albicans,and 90％and 62.5％against Staphylococcus aureus,respec-tively.Based on the results of antibacterial experiments in vitro,the anti-inflammatory activity of BS2-1-MVs in vivo was studied.The results showed that BS2-1-MVs can effectively improve the symptoms of DSS induced ulcerative colitis in mice,including body weight,disease activity index,colon length and tissue le-sion degree,and has strong anti-inflammatory activity.Conclusion:By optimizing the medium and culture conditions,the yield of MVs was increased.The antibacterial efficiency of BS2-1-MVs against C.albicans and S.aureus was higher than that of BS579-MVs,and BS2-1-MVs had strong anti-inflammatory activity,which laid the foundation for the development of new high-efficiency anti-inflammatory drugs in the fu-ture.