Liquid Nitrogen Storage of Yeast Cultures Compared to More Traditional Storage Methods. I. Russell and G. G. Stewart, Brewing Research and Development, Labatt Breweries of Canada, Ltd., London, Ontario, N6A 4M3. J. Am. Soc. Brew. Chem. 39:0019, 1981.

Twelve brewing yeast strains were stored for a two-year period under a variety of conditions in order that an ideal method for the storage of such cultures could be determined. Liquid nitrogen storage was found to be the method of choice if cost and availability of liquid nitrogen were not significant factors. Cultures stored in liquid nitrogen had the lowest death rate and were the easiest to revitalize; the degree of flocculation, the fermentative rate, sporulation ability, and giant colony plate morphology were unaffected. The proportion of respiratory-deficient and glycogen-deficient mutants did not increase. Storage at 4° C on nutrient agar slopes sub-cultured every six months was the next method of preference. Lyophilization and other storage methods revealed yeast instability that varied from strain to strain.

Keywords: Brewer's yeast, Culture collection, Liquid nitrogen, Storage, Yeast