Technical Session 14: Yeast II Session
Diego Libkind, INIBIOMA, Bariloche, ARgentina
ABSTRACT: The lager-brewing yeast (Saccharomyces pastorianus) is a domesticated microbe arising through the hybridization between S. cerevisiae (ale yeast) and a cryotolerant Saccharomyces
relative as a result of cold brewing practices that Bavarian brewers
made famous in the 15th century. Despite being available as pure culture
since the late 1800s, its hybrid genetic nature was only discovered a
few decades ago. So far, all the industrial or wild strains isolated of
cold adapted Saccharomyces have been discarded as progenitor
candidates due to considerable genetic dissimilarities or due to hybrid
condition. Recently, a worldwide survey yielded a novel yeast dubbed S. eubayanus
from Patagonian native forests of Argentina that was shown to be the
closest known match (99.5%) to the non-ale portion of lager yeasts and,
thus, its putative progenitor. Identifying the wild genetic stock of the
cryotolerant side of S. pastorianus allowed resolution of the
hitherto confusing taxonomy of the most relevant brewing yeast and the
understanding of key events that led to the domestication of lager
yeast. For example, specific genetic changes related to sugar and
sulfite metabolism were detected in lager yeasts when compared to S. eubayanus.
Furthermore, the available information relevant to the discussion on
how and when such a half European and half Patagonian yeast hybrid might
have been originated will be addressed in this presentation.
Libkind, licenciate in biological sciences (2001); Ph.D. degree, in
Biochemistry, Comahue’s National University, Bariloche, Argentina
(2006); Tucuman National University, Argentina. Researcher of the
Argentinean National Council on Science and Technology Research
(CONICET); teaching assistant in genetics, Comahue National University.
Dedicated to the investigation of yeast biodiversity and biotechnology
with special focus on Patagonian natural habitats and with over 50
publications on the field. Member of the ASBC Craft Brewers Committee
and of the International Commission on Yeasts.