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CHILL PROOFING BY A STRAIN OF SACCHAROMYCES CEREVISIAE SECRETING PROTEOLYTIC ENZYMES
Author(s) -
Sturley S. L.,
Young T. W.
Publication year - 1988
Publication title -
journal of the institute of brewing
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.523
H-Index - 51
eISSN - 2050-0416
pISSN - 0046-9750
DOI - 10.1002/j.2050-0416.1988.tb04569.x
Subject(s) - proteases , brewing , protease , fermentation , yeast , saccharomyces cerevisiae , biochemistry , extracellular , enzyme , strain (injury) , biology , proteolytic enzymes , food science , chemistry , anatomy
The attempted exploitation of a strain of yeast with extracellular protease activity in the fermentation of brewers' wort is described. S. cerevisiae strain YS01 was previously shown to secrete proteases with activity against a variety of substrates. It is shown here that these included some of the tannin precipitable proteins involved in the formation of chill haze in beer and consequently, more stable beers resulted from incubation with added YS01 cell‐free culture supernatants. The proteases were also produced in an active form at low levels during fermentation of brewers' wort using established commercial conditions. Concomitantly, a marginally more stable beer resulted. Respiratory deficient, auxotrophic rare‐mating was used to transfer the extracellular proteolytic characteristic ( epr1.1 ) to a commercial ale yeast. Segregants of the recombinants obtained showed great instability in protease secretion and were unsuitable for brewing purposes. The potential advantages and drawbacks to this approach are discussed.