Fructose fermentation and assimilation by yeasts


Fructose fermentation and assimilation by yeasts

There are much more than 1,500 described yeast species, about a half of which belongs to Ascomycota. More than 70% of ascomycetous yeast species has an ability of ethanol fermentation. Sugars utilized for ethanol fermentation by yeasts vary from species to species, which has been regarded as ‘personality’ (namely salient characteristics of phenotype). For example, Saccharomyces cerevisiae, a star yeast species for scientific researches, can utilize glucose, maltose, and sucrose for ethanol fermentation, but not lactose.

Species identification of yeasts has been done by recognizing such phenotypic differences since the dawn of yeast taxonomy. Thanks to the history of yeast taxonomy, ‘personal information’ of yeast species (data of the abilities to ferment and assimilate various kinds of carbon and nitrogen sources) has long been accumulated. Unfortunately, however, very few ‘personal information’ regarding fructose, a very common sugar in nature, was not available until recently.

In order to obtain the missing information, we examined 388 strains of yeast stocked in RIKEN BRC-JCM, mainly belonging to the Saccharomycetes (Saccharomycotina, Ascomycota), determining whether they can assimilate/ferment fructose by conventional methods using liquid medium. As the results, all strains examined assimilated fructose, whereas 302 (77.8%) of them fermented fructose. These results strongly suggest that the ability to assimilate/ferment fructose is a universal phenotype among yeasts in the Saccharomycetes. We might miss out such a fundamental ‘personal information’ which would enhance the utility of yeasts as bioresources.

But, why? Why have the ‘personal information’ regarding abilities to assimilate/ferment fructose by yeasts long been neglected? During the course of searching reasons, we had been faced with the unexpected historical background…
Please go check details of the story in the reference below!

Rikiya Endoh, Maiko Horiyama, and Moriya Ohkuma,
“D-Fructose assimilation and fermentation by yeasts belonging to Saccharomycetes: Rediscovery of universal phenotypes and elucidation of fructophilic behaviors in Ambrosiozyma platypodis and Cyberlindnera americana“, Microorganisms, microorganisms9040758


Ethanol fermentation by yeast (130MB)

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