Intensive Bioethanol Production Using Date Stems By-products and Natural Sugars

Date Stem By-products (DSB) have been used as agricultural feedstock to perform bioethanol production in a batch bioreactor. To study the effect of an optimal mixture of fruit hydrolysates (20%dates, 20% Figs, and 20% sugar beet) on ethanol yield, different parameters have been followed up, including pH, total sugars, and ethanol yield. The optimal ethanol concentration was found for date stems by-products +20% dates, it was about 19.38 g/L after 72h fermentation process, in such case, the higher initial sugar concentration is close to 204.5 g/L, and the pH dropped from 4.5 to 4.21, while it was only about 18.48, 13.08 and 4.72 g/L for DSB+20% sugar beet, DSB+20% Figs, and DSB, respectively. The maximum bioethanol production rate (Rm) was about 2.633 (g/L/h) in the case of DSB+20% dates, which is higher compared to the other selected mixtures. The effect of some physical properties on the addition of ethanol/ETBE (Ethyl tertiary-butyl ether) to super-premium gasoline has been studied. It was found that the addition of 20% ethanol or ETBE to super-premium gasoline increased the Research Octane Number from 96 up to 99.3 and from 96 up to 99.8 in the case of DSB+20% dates and ETBE, respectively.