The yeast flora of ensiled whole‐crop maize

Abstract

AbstractThe yeast flora in samples of 13 different whole‐crop maize silages was shown to be predominated by Candida krusei, C. lambica, Saccharomyces dairensis, S. exiguus, C. holmii or C. milleri. All these strains fermented glucose but, except for the latter three species, not sucrose, α‐trehalose or raffinose. Under conditions resembling those in silage, i.e. at pH 4.0 in the presence of a complex nitrogen source, all strains assimilated lactic and acetic acids. This result suggests that the predominant yeasts in silage should not be distinguished into lactate utilisers and lactate non‐utilisers. All strains, except those of Saccharomyces dairensis, tolerated acetic acid (5 g litre−1) and grew at pH 4.0 in a mineral salts medium containing lactic acid (10 g litre−1), acetic acid (5 g litre−1) and yeast extract (1 g litre−1). Growth in this medium was completely inhibited by the cationic detergent Arquad C33W (20 mg litre−1), propionic acid (5 g litre−1), benzoic acid (5 g litre−1) or salicylic acid (10 g litre−1).