Js. Leyva et al., Regulation of fermentative CO2 production by the food spoilage yeast Zygosaccharomyces bailii, ENZYME MICR, 24(5-6), 1999, pp. 270-275
Zygosaccharomyces bailii is a yeast that spoils foods by CO2 accumulation.
Gas is mainly produced by alcoholic fermentation. To study the extent and r
egulation of fermentative CO2 production in this yeast, we have evaluated t
he relevance of the effect of oxygen (Pasteur effect) and sugar (Crabtree e
ffect) concentrations. In controlled-batch cultures on glucose and fructose
, the main difference observed was that catabolism on fructose was not affe
cted by oxygen concentration while on glucose, ethanol production increased
in the absence of oxygen. This behavior can be explained by a higher capac
ity to transport fructose and the Crabtree effect. Manometric experiments w
ith resting cells confirmed the limited respiratory capacity of Z. bailii a
nd that, under these nongrowing conditions, cells retained the ability of p
roducing an important amount of gas. The Pasteur effect was not important i
n Z. bailii since the glucose kinetic parameters in continuous cultures Ir
ere trot significantly affected by the oxygen concentration Continuous cult
ure experiments also that the amount of gas produced depended on the oxygen
concentration and the sugar consumption rate. For low sugar concentrations
which imply low consumption rates, oxygen concentration was an important c
ontrolling factor; however, at high sugar consumption rates, gas production
became independent of oxygen concentration, or in other words, regulation
was dominated by the Crabtree effect. (C) 1999 Elsevier Science Inc.