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Attachment of MAL32 ‐encoded maltase on the outside of yeast cells improves maltotriose utilization
Author(s) -
Dietvorst J.,
Blieck L.,
Brandt R.,
Van Dijck P.,
Steensma H. Y.
Publication year - 2007
Publication title -
yeast
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.923
H-Index - 102
eISSN - 1097-0061
pISSN - 0749-503X
DOI - 10.1002/yea.1436
Subject(s) - maltotriose , brewing , maltose , lactose permease , biology , fermentation , maltase , yeast , saccharomyces cerevisiae , biochemistry , enzyme , gene , transporter , permease
The fermentation of maltotriose, the second most abundant fermentable sugar in wort, is often incomplete during high‐gravity brewing. Poor maltotriose consumption is due to environmental stress conditions during high‐gravity fermentation and especially to a low uptake of this sugar by some industrial strains. In this study we investigated whether the use of strains with an α‐glucosidase attached to the outside of the cell might be a possible way to reduce residual maltotriose. To this end, the N‐terminal leader sequence of Kre1 and the carboxy‐terminal anchoring domain of either Cwp2 or Flo1 were used to target maltase encoded by MAL32 to the cell surface. We showed that Mal32 displayed on the cell surface of Saccharomyces cerevisiae laboratory strains was capable of hydrolysis of α‐1,4‐linkages, and that it increased the ability of a strain lacking a functional maltose permease to grow on maltotriose. Moreover, the enzyme was also expressed and found to be active in an industrial strain. These data show that expressing a suitable maltase on the cell surface might provide a means of modifying yeast for more complete maltotriose utilization in brewing and other fermentation applications. Copyright © 2007 John Wiley & Sons, Ltd.