High yield production of a soluble bifidobacterial β-galactosidase (BbgIV) inE. coliDH5α with improved catalytic efficiency for the synthesis of prebiotic galactooligosaccharides

Osman, A., Tzortzis, G., Rastall, R. and Charalampopoulos, D. ORCID: https://orcid.org/0000-0003-1269-8402 (2013) High yield production of a soluble bifidobacterial β-galactosidase (BbgIV) inE. coliDH5α with improved catalytic efficiency for the synthesis of prebiotic galactooligosaccharides. Journal of Agricultural and Food Chemistry, 61 (9). pp. 2213-2223. ISSN 0021-8561 doi: 10.1021/jf304792g

Abstract/Summary

The bifidobacterial β-galactosidase (BbgIV) was produced in E. coli DH5α at 37 and 30 °C in a 5 L bioreactor under varied conditions of dissolved oxygen (dO2) and pH. The yield of soluble BbgIV was significantly (P < 0.05) increased once the dO2 dropped to 0–2% and remained at such low values during the exponential phase. Limited dO2 significantly (P < 0.05) increased the plasmid copy number and decreased the cells growth rate. Consequently, the BbgIV yield increased to its maximum (71–75 mg per g dry cell weight), which represented 20–25% of the total soluble proteins in the cells. In addition, the specific activity and catalytic efficiency of BbgIV were significantly (P < 0.05) enhanced under limited dO2 conditions. This was concomitant with a change in the enzyme secondary structure, suggesting a link between the enzyme structure and function. The knowledge generated from this work is very important for producing BbgIV as a biocatalyst for the development of a cost-effective process for the synthesis of prebiotic galactooligosaccharides from lactose.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/32370
Item Type	Article
Refereed	Yes
Divisions	Life Sciences > School of Chemistry, Food and Pharmacy > Department of Food and Nutritional Sciences > Food Research Group
Publisher	American Chemical Society
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