Production of biofuel from Washingtonia fruits by anaerobic digestion with Saccharomyces cerevisiae: Process optimization

Abstract

In this study, we contributed to produce bioethanol from washingtonia fruits. The production of bioethanol is ensuring by saccharification and fermentation in the presence of the yeast Saccharomyces cerevisiae. The physico-chemical properties of washingtonia fruits and produced bioethanol were determined. In order to optimize the fermentation process, batch experiments were carried out to study the effect of some operating parameters: initial dose of substrate (10, 15, 20, 25 and 30 g/L). dose of yeast (0.4, 0.8 and 1.2 g/L) and the fermentation time (24, 48 and 72 h). During fermentation. we followed the pH, density, alcoholic degrees and the refractive index of the produced bioethanol. The optimal conditions revealed from these experiments are as follows: 10 g/L for the dose of substrate, 0.4 g/L for the yeast dose and 72 h for the fermentation time. Best bioethanol yield (54.18 %), degree (96°) and refractive index (1.361) were observed under optimal process conditions. The flammability test and the analysis by Fourier transform infrared spectroscopy (FTIR) have confirmed the good quality of the produced bioethanol and this latter has a heat capacity of 24346 kJ/kg. The results of this study show that Washingtonia fruits have a great potential for the production of bioethanol which could be advantageously used as biofuel.