A food-grade industrial arming yeast expressing β-1,3-1,4-glucanase with enhanced thermal stability
A food-grade industrial arming yeast expressing β-1,3-1,4-glucanase with enhanced thermal stability
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DOI：
10.1631/jzus.b0900185
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发表时间：
2010-01
期刊：
影响因子：
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通讯作者：
Qin Guo;W. Zhang;Liu-liu Ma;Qihe Chen;Ji-cheng Chen;Hong-bo Zhang;H. Ruan;G. He
中科院分区：
文献类型：
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作者：
Qin Guo;W. Zhang;Liu-liu Ma;Qihe Chen;Ji-cheng Chen;Hong-bo Zhang;H. Ruan;G. He
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.
