Use of waste date products in the fermentative formation of bakerʹs yeast biomass by Saccharomyces cerevisiae

This work was an approach to waste date products valorization through biomass production with the yeast Saccharomyces cerevisiae. The carbon and nitrogen sources of a semi-synthetic fermentation medium were substituted by date-coat (fleshy part) sugar extract, date-seed hydrolysate, and ammonium nitrate. This modified medium was enriched with date-seed ash and date-seed lipid. Date-coat sugar extract as a carbon source was found to be satisfactory at a concentration of 25 g/l (expressed as its glucose concentration) and date-seed hydrolysate as a nitrogen source was equally suitable at 25 g/l. The addition to the medium of 1•0 g/l ammonium nitrate increased the efficiency of yeast biomass formation, as did phosphorus, which produced a maximum when the medium was supplemented with about 6•0 g/l KH2PO4. The presence of 1 g/l date-seed lipid in the medium also increased the efficiency of biomass formation. Finally, the addition of date-seed ash (0•6 g/l), as a mineral source, to the fermentation medium could substitute for MgSO4 and CaCl2 of the semi-synthetic medium.