Expression of Vitreoscilla hemoglobin in Bacillus thuringiensis improve the cell density and insecticidal crystal proteins yield.
The Vitreoscilla hemoglobin (VHb) gene (vgb) was integrated into the chromosome of Bacillus thuringiensis BMB171 using integrative vector pEG491. The production of VHb was confirmed by CO-difference spectra analysis. Fermentation experiments results showed that with the production of VHb, the critical oxygen concentration (COC) of the host strain was reduced from 18 to 12%. The maximum viable cell counts of the VHb+ strain in high, middle, and low aeration/agitation fermentations were 0.94-, 1.23-, and 1.59-fold of those of the VHb- strain, respectively. Under the same conditions, the yields of insecticidal crystal proteins (ICP) by VHb+ strain were 1.22-, 1.63-, and 3.13-fold of those of the VHb- strain. The production of VHb also accelerated the formation of ICP and spores. These results indicated that the production of VHb could improve the cell density and ICP yield of B. thuringiensis, especially under low aeration/agitation condition.
Liang
Feng
F
State Key Laboratory of Agricultural Microbiology, National Engineering Research Center for Microbial Pesticides, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.
Shouwen
Chen
C
Ming
Sun
S
Ziniu
Yu
Y
D001413:Bacillus thuringiensis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001427:Bacterial Toxins / Q000378:metabolism*; D001709:Biotechnology / Q000379:methods; D003470:Culture Media; D004731:Endotoxins / Q000378:metabolism*; D005285:Fermentation; D005818:Genetic Engineering / Q000379:methods; D006454:Hemoglobins / Q000235:genetics / Q000378:metabolism*; D006460:Hemolysin Proteins / Q000378:metabolism*; D010100:Oxygen / Q000494:pharmacology; D010957:Plasmids / Q000235:genetics; D011995:Recombination, Genetic; D054793:Truncated Hemoglobins; D020589:Vitreoscilla / Q000235:genetics / Q000378:metabolism*
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D003470:Culture Media; D004731:Endotoxins; D006454:Hemoglobins; D006460:Hemolysin Proteins; D054793:Truncated Hemoglobins; C030956:insecticidal crystal protein, Bacillus Thuringiensis; C082613:hemoglobin protein, Vitreoscilla; D010100:Oxygen