*2.3. Preparation of Culture Medium Based on the Dates Extract and Inoculums*

The method cited by Kocher and Uppal [25] was used with minor modifications. The obtained date extract from the above preparation was supplemented by mineral salts: magnesium sulfate 0.44 g, urea 12.70 g, and ammonium sulfate 5.30 g. Finally, the medium was distributed in an Erlenmeyer of 250 mL with a ratio of 100 mL per flask and sterilized at 120 ◦C for 20 min. The pre-culture was obtained by inoculating two colonies of the yeast *S. cerevisiae* in 250 mL shake flasks containing 100 mL of dates extract, mentioned above. The pre-culture was incubated at 30 ◦C for 3 h, and used further as inoculums for the yeast biomass production.
