Galactose yeasts

Racemic mannose yeast- /-mannose + C02 + ethanol Similarly, (/-glucose, /-fructose, or (/-galactose yeasl> C02 + ethanol However, /-glucose, (/-fructose, or /-galactose yeast > no fermentation... 

Another microbial polysaccharide-based emulsifier is Hposan, produced by the yeast Candida lipolytica when grown on hydrocarbons (223). Liposan is apparentiy induced by certain water-immiscible hydrocarbons. It is composed of approximately 83% polysaccharide and 17% protein (224). The polysaccharide portion consists of D-glucose, D-galactose, 2-amino-2-deoxy-D-galactose, and D-galacturonic acid. The presence of fatty acyl groups has not been demonstrated the protein portion may confer some hydrophobic properties on the complex. 

Some yeasts are able to add other monosaccharides, like galactose (S. pombe), but with unusual bonds [70], and they also tend to phosphorylate their glycans everywhere to obtain an additional charge on proteins [71]. 

If branching is (1 —> 3), no glycol grouping will be present in any central unit and it may be seen that reaction will only occur on the terminal units. Such is the case with the polysaccharide laminarin, with the glucan of yeast membrane, and with a galactose-containing polysaccharide isolated from agar.146-148... 

Most of our present information on the conversion of galactose to glucose has come from the study of microorganisms, particularly the yeast Saccharomyces fragilis. However, there is ample evidence that the same metabolic paths are followed in mammalian tissue. 

Reaction (1) is irreversible the enzyme galactokinase has been found in mammalian liver, brain, and erythrocytes, as well as in certain yeasts and other microorganisms. UDPGal, the main product of reaction (2), is the intermediate by means of which the body incorporates galactose into cerebrosides and, probably, other galactolipids, mucopolysaccharides, and lactose galactose-l-phosphate uridyl transferase occurs in the liver, to a lesser extent in red cells, and probably in other tissues. 

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