Utilization of Saudi date sugars in production of bakerʹs yeast

Six different yeasts: Saccharomyces cerevisiae (I); S. dastorianus NRRL Y-12693; S. cerevisiae (II); S. dayanus NRRL Y-12624; S. cerevisiae NRRL Y-12632 and S. lodgwii were cultivated in different fermentation media. The results showed that S. cerevisiae (I) gave the highest biomass production. Sefry Beesha dates contained 60% total reducing sugars. When blackstrap molasses, the carbon source of the fermentation medium, was replaced by an equivalent amount of Sefry Beesha date sugars, they were as suitable as the molasses in the production of yeast. The best datesugar concentration was 50•0 mg/ml. Ammonium sulphate was a good nitrogen source, at a concentration of 2•0 mg/ml, for the production of yeast biomass. Biotin, at a concentration of 50 μg/l, was a good growth stimulator for S. cerevisiae (I). The ash of S. cerevisiae (I) contained Na, Mg, Ca, Fe, Zn and Cu. Cobalt and Ni were not detected. The concentrations of these metals in the bakerʹs yeast are non-toxic.