Sugars utilized by yeasts

D Amore, T., Russell, 1., Stewart, G. G. (1989). Sugar utilization by yeast during fermentation. Journal of Industrial Eermentation, 4, 315-344. 

Owen (99) studied the effect of bacterial contaminants on the efficiency of sugar utilization by yeast in molasses fermentations. His results did not yield a clear-cut indication that the contaminants were always harmful. Fluorides as antiseptics improved the efficiency in heavily contaminated mashes. However, they also had a beneficial effect in the same mashes sterilized by heat before seeding. The conclusion is that the effect of contaminants depends on the stage at which they are introduced and on the effect per se of the countermeasures taken. It must be borne in mind that other factors than the mere killing of the bacteria enter the picture. These other factors may themselves alter the course of the fermentation and thus make interpretation difficult. 

Kuyper, M., Toirkens, M. J., Diderich, J. A., Winkler, A. A., Van Dijken, J. R, Pronk, J. T. (2005). Evolutionary Engineering of mixed-sugar utilization by a xylose-fermenting Saccharomyces cerevisiae strain. FEMS Yeast Research, 5, 925-934. 

These theoretioal yields of CO. and of alcohol are never reached. The reason for the reduced yields was explained by Pasteur who found that other products than alcohol and carbon dioxide were produced in alcoholic fermentation of sugars. He also called attention to the fact that some sugar is utilized by yeasts in building new yeast cells. Pasteur obtained 48.3 per cent of alcohol and 46.4 per cent of carbon dioxide. 

Catalysis is not a new phenomenon, but its intentional utilization by humans has begun only in this century. One of the first catalytic processes was probably the fermentation of fruits to obtain alcoholic beverages. Enzymes found in yeast were used as catalysts for the conversion of sugar into alcohol. In fact, ancient Sumerians described beer preparation on... 

In certain instances, the exocellular and intracellular polysaccharides of yeasts have been used by taxonomists as an aid in classification of the parent organisms. For example, Lipomyces lipoferus may readily be distinguished from Lipomyces starkeyi by the sugars formed on partial and on complete hydrolysis of their exocellular polysaccharides (see Table VII), a differentiation that is difficult if morphological characteristics and sugar-utilization patterns are used. ... 

The utilization of sugars by yeasts has long been turned to account in making leavened bread, wine, and beer. An early industrial exploitation of microbial biochemistry was the manufacture of glycerol during the First World War by the addition of sulfite to a fermenting mixture of yeast and sugar 7 9 for a review, see Ref. 10. Since then, a... 

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