Production of Bioethanol from Olive Solid Waste JEFT

Abstract

Renewable energy sources have received increased interest from the international community with biomass being one of the oldest and the most promising ones. In the concept of exploitation of agro-industrial residues, the present study investigates the pre-treatment and ethanol fermentation potential of the olive pulp. Olive solid residue (jeft) is the solid waste generated during olive oil production process in three-phase olive mills. It consists of the remaining pulp of olive processing after the extraction of oil, as well as the cracked seeds of the olive fruits. As a lignocellulosic material, the hemicellulose, cellulose and lignin are the main components of olive stone. In our study we have standardized the production of ethanol from olive solid wastes using Saccharomyces cerevisiae strains which isolated from yogurt, grape and sugarcane. These strains were identified according to morphological and biochemical characterization tests characters in comparison with the commercial standard strain S. cerevisiae hismaya. In alcohol tolerance test, S. cerevisiae tolerate up to 10% of ethanol in the medium. Optimization of culture condition such as pH and temperature of yeast strain for different yeast strains was done. 10g Jeft was subjected to hydrolysis to sugar by acids such as 5% HCl and microwave assisted with 5% HCl at 90°C in shaker water path for 3 hours. The fermentation process was carried out in jeft under optimum conditions such as pH4.5, temperature 30°C and incubated for 72 hrs. The maximum amount of ethanol production (9.3 g/l) was observed by using Ethanol Assay Kit. Compared with convection mode of heating of dilute 5% HCl hydrolysis, the microwave assisted 5% HCl process improved the yield of ethanol by 33.3% compared to the non-microwave process.