Aerobic sugar metabolism in the spoilage yeast

Abstract

Despite the importance of some Zygosaccharomyces species as agents causing spoilage of food, the carbon and energy metabolism of most of them is yet largely unknown. This is the case with Zygosaccharomyces bailii. In this study the occurrence of the Crabtree effect in the petite-negative yeast Z. bailii ATCC 36947 was investigated. In this yeast the aerobic ethanol production is strictly dependent on the carbon source utilised. In glucose-limited continuous cultures a very low level of ethanol was produced. In fructose-limited continuous cultures ethanol was produced at a higher level and its production increased with the dilution rate. As a consequence, on fructose the onset of respiro-fermentative metabolism caused a reduction in biomass yield. An immediate aerobic alcoholic fermentation in Z. bailii was observed during the transition from sugar limitation to sugar excess, both on glucose and on fructose. The analysis of some key enzymes of the fermentative metabolism showed a high level of acetyl-CoA synthetase in Z. bailii growing on fructose. At high dilution rates, the activities of glucose- and fructose-phosphorylating enzymes, as well as of pyruvate decarboxylase and alcohol dehydrogenase, were higher in cells during growth on fructose than on glucose.

Lipidomic Profiling of Saccharomyces cerevisiae and Zygosaccharomyces bailii Reveals Critical Changes in Lipid Composition in Response to Acetic Acid Stress

“…Z. bailii exhibited a 16% lower Y EtOH/s than S. cerevisiae , probably due to the less extensive overflow metabolism, as described elsewhere [44]. When the cells were exposed to acetic acid, Z. bailii exhibited a 69% lower Y EtOH/s than S. cerevisiae (Table 3).…”

The Genome Sequence of the Highly Acetic Acid-Tolerant Zygosaccharomyces bailii-Derived Interspecies Hybrid Strain ISA1307, Isolated From a Sparkling Wine Plant

“…6,18,21,22 The genome sequence of the ISA1307 hybrid strain and of the type strain Z. bailii CLIB213 T were searched for homologues of the Snf1-signalling pathway, known to play a prominent role in glucose repression in S. cerevisiae 52 (Table 3). No significant differences were registered in the amino acid sequence of the proteins predicted to function in the Snf1-signalling pathway in ISA1307 and in Z. bailii CLIB213 T , indicating that this pathway should function in a similar manner in the two strains (results not shown).…”

“…1,2 Zygosaccharomyces bailii is known to vigorously ferment hexoses and, like other members of the Zygosaccharomyces genus, Z. bailii exhibits a frutophilic behaviour metabolizing fructose at a higher rate than glucose when the two carbon sources are present in the growth medium. 2,5,6 Moreover, Z. bailii is able to cause spoilage from an extremely low inoculum, to tolerate moderate osmotic pressure and to grow at high growth rates under oxygen-restrictive conditions. 2,7 Food products that are preserved at low pH, low water activities or low oxygen concentrations, and that contain adequate amounts of fermentable sugars, are therefore at a particular risk of spoilage by this yeast, causing significant economic losses for the industries that produce and commercialize these products.…”

Fermentation kinetics and chemical characterisation ofvino tostado, a traditional sweet wine from Galicia (NW Spain)

“…45 Zygosaccharomyces bailii shows a higher ability to ferment fructose than glucose, 46 glucose transport being inhibited by the presence of fructose. 47 The stoppage of the spontaneous fermentation that took place at 28…”