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| A food-grade industrial arming yeast expressing β-1,3-1,4-glucanase with enhanced thermal stability |
| Qin GUO, Wei ZHANG, Liu-liu MA, Qi-he CHEN, Ji-cheng CHEN, Hong-bo ZHANG, Hui RUAN, Guo-qing HE |
| Department of Food Science and Nutrition, Zhejiang University, Hangzhou 310029, China; Wenzhou Medical College, Wenzhou 325035, China |
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Abstract The aim of this work was to construct a novel food-grade industrial arming yeast displaying β-1,3-1,4-glucanase and to evaluate the thermal stability of the glucanase for practical application. For this purpose, a bi-directional vector containing galactokinase (GAL1) and phosphoglycerate kinase 1 (PGK1) promoters in different orientations was constructed. The β-1,3-1,4-glucanase gene from Bacillus subtilis was fused to α-agglutinin and expressed under the control of the GAL1 promoter. α-galactosidase induced by the constitutive PGK1 promoter was used as a food-grade selection marker. The feasibility of the α-galactosidase marker was confirmed by the growth of transformants harboring the constructed vector on a medium containing melibiose as a sole carbon source, and by the clear halo around the transformants in Congo-red plates owing to the expression of β-1,3-1,4-glucanase. The analysis of β-1,3-1,4-glucanase activity in cell pellets and in the supernatant of the recombinant yeast strain revealed that β-1,3-1,4-glucanase was successfully displayed on the cell surface of the yeast. The displayed β-1,3-1,4-glucanase activity in the recombinant yeast cells increased immediately after the addition of galactose and reached 45.1 U/ml after 32-h induction. The thermal stability of β-1,3-1,4-glucanase displayed in the recombinant yeast cells was enhanced compared with the free enzyme. These results suggest that the constructed food-grade yeast has the potential to improve the brewing properties of beer.
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Received: 01 July 2009
Published: 01 January 2010
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Cite this article:
Qin GUO, Wei ZHANG, Liu-liu MA, Qi-he CHEN, Ji-cheng CHEN, Hong-bo ZHANG, Hui RUAN, Guo-qing HE. A food-grade industrial arming yeast expressing β-1,3-1,4-glucanase with enhanced thermal stability. Journal of Zhejiang University-SCIENCE B (Biomedicine & Biotechnology), 2010, 11(1): 41-51.
URL:
http://www.zjujournals.com/xueshu/zjus-b/10.1631/jzus.B0900185 OR http://www.zjujournals.com/xueshu/zjus-b/Y2010/V11/I1/41
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