Production of Bioethanol from Palm Tree’s Wastes by Enzymatic Hydrolysis and Fermentation

Abstract

This work attempted to convert some of the wastes of palm tree (Phoenix dactylifera L.) into bioethanol, namely, leaflets, seeds and dates. The leaflets and seeds were ground and pretreated by three methods: direct fermentation, enzymatic hydrolysis (0.1 and 0.3) g/g and diluted alkaline (NaOH) followed by enzymatic hydrolysis. The dates were fermented directly by (Saccharomyces cerevisiae) with different yeast to dates ratios of (0.05, 0.1 and 0.25) g/g and at (25 and 35) °C. The results showed that the highest bioethanol yields for leaflets and seeds were (13.3 ± 0.6) g and (15.5 ± 0.4) g, respectively, achieved by enzymatic hydrolysis 0.3 g/g for 48h, followed by fermentation by yeast to sample ratio of 0.1 g/g at 35 °C. Whereas, the results of the dates experiments showed a shortest fermentation time of 7 h by yeast to dates ratio of 0.25 g/g at 35 °C at which the bioethanol production rate was 4.55 g/h. The maximum yield bioethanol of from dates was (31.9 ± 0.5) g. Correlations for the effects of temperature and yeast to dates ratio on the bioethanol production time were developed.