Co-expression of β-glucosidase and Vitreoscilla hemoglobin in Escherichia coli.
- Author:
Fajun DENG
1
;
Yu PAN
1
;
Fei CHANG
1
;
Wei FANG
1
;
Zemin FANG
1
;
Yazhong XIAO
1
Author Information
- Publication Type:Journal Article
- Keywords: Escherichia coli; Vitreoscilla hemoglobin (VHb); bicistron; β-glucosidase
- From: Chinese Journal of Biotechnology 2018;34(3):379-388
- CountryChina
- Language:Chinese
- Abstract: In producing recombinant β-glucosidase in Escherichia coli by high-cell density cultivation (HCDC), insufficient soluble oxygen is always a problem. To address it, Vitreoscilla hemoglobin (VHb) was introduced into Escherichia coli by the bicistron and T₇ promoter expression systems, to improve soluble oxygen by bacterial cells and thereby to enhance the biomass and recombinant β-glucosidase production. In the case of bicistron expression system, cell density in shaking flask reached OD₆₀₀=(4.24±0.29), 35.03% higher than that of the control without VHb. Correspondingly, the maximum activity of β-glucosidase co-expressed with VHb was (9.78±0.55) U/mL, 25.38% higher than that of the control. In a 3-L fermentor, the maximum activity of β-glucosidase was 141.23 U/mL, 35.57% higher than that of the control. In contrast, the activity of β-glucosidase co-expressed with VHb under T₇ promoter was lower than that of the control, either in flask or in fermentor. Co-expressing β-glucosidase with VHb using the bicistron expression system may improve the tolerance of E. coli to insufficient soluble oxygen and thus promote the bacterial biomass and the enzyme yield.
