Effect of menD expression on vitamin K2 production in Bacillus subtilis
Vitamin K2(MK)is an important natural compound,which plays an important role in the treatment of various diseases.To determine the role of menD in MK synthesis in Bacillus subtilis,the effects of the different expression levels of menD on bacterial growth,biofilm morphology,and MK production were detected by constructing BS168-ΔmenD,BS168-P43-menD and BS168-PxylA-menD.The ex-pression intensity of the menD was detected by western-blot and the content of MK was detected by HPLC.The experimental result showed that the BS168-ΔmenD strain failed to form biofilm and couldn't grow well when standard menadione wasn't added in the medium.The biofilm and the MK content of BS168-P43-menD and BS168-PxylA-menD were significantly different from the original strain BS168.During static fermentation,the biofilm biomass and wrinkle degree of BS168-P43-menD and BS168-PxylA-menD were greatly increased.The biofilm biomass of BS168-P43-menD and BS168-PxylA-menD were 1.36 and 1.59 times that of the original strain,respectively.The MK contents of BS168-P43-menD,BS168-PxylA-menD were 1.64 and 1.87 times that of the original strain,respectively.The maximum yield of MK was 39.27 mg/L in BS168-PxylA-menD.The results indicated that the expression level of menD was an important factor affecting the formation of biofilm and MK in B.subtilis.
Bacillus subtilisvitamin K2promoterexpression intensitybreeding of strains
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