INFLUENCE OF OXYGEN ON FERMENTATION PATTE RN IN MODEL MEDIA CONTAINING MIXED OR SEQUENTIAL CULTURES OF 3 CIDER-PRODUCING YEASTS - SACCHAROMYCES-CEREVISIAE, VAR UVARUM, HANSENIASPORA-VALBYENSIS AND METSCHNIKOWIA-PULCHERRIMA

Pure, mixed and sequential cultures of Saccharomyces cerevisiae var. u varum, Hanseniaspora valbyensis and Metschnikowia pulcherrima were stu died in batch cultures, on synthetic media and after partial oxygenati on. In mixed cultures, development of S. cerevisiae prevents the impla ntation of H. valbyensis and M. pulcherrima. In this case, fermentatio n was conducted by S. cerevisiae, whatever oxygenation level of medium . Volatile compounds produced were essentially higher alcohols, ethyl acetate, acetaldehyde and acetoin. In sequential cultures, growth of H . valbyensis, which is linked to oxygenation of medium, delayed develo pment of S. cerevisiae and the pattern of production of volatile compo unds reflected the patterns characteristic of each strain. M. pulcherr ima inhibited S. cerevisiae, and production of volatile compounds was greatly reduced.