Study On The Function And Expression Of Vitreoscilla Hemoglobin Gene In Bacillus Amyloliquefaciens FZB42

The Vitreoscilla hemoglobin (VHb) gene (vgb) was placed under the control of the P43 promoter by overlapping extension PCR. The vgb expression cassette was integrated into the amyE gene locus of Bacillus amyloliquefaciens FZB42 chromosome using integrative vector pDG1730 containing two recombination arm of amyE gene. The recombinated integron was confirmed by Colony PCR. The production of VHb was confirmed by SDS-PAGE, Western-Blot and CO-difference spectra analysis.To study the effect of the expression of VHb on the recombinated strain FZB42-VHb, the growth of the strain and the yield of the antimicrobial lipopeptide were observed. The result showed that expssion of VHb promoted the growth of the strain and improved the yield of the antimicrobial lipopeptide. The maximum viable cell counts of the FZB42-VHb strain were 1.14 fold of those of the host strain. Under the same conditions,the yield of the antimicrobial lipopeptide Fengycin and Surfactin were 1.74-,3.14-fold of those of the host strain,respectively. The antimicrobial lipopeptide inhibitory activity on Rhizoctonia solani, Sclerotium rolfsi,Alternaria alternata were improved by 61.5%, 36.4% 38.9%, respectively.