2016 : The effect of pretreatment and variety of microorganisms to the production of ethanol from coffee pulp

Prof.Ir. Ali Altway M.Sc
Prof. Dr. Ir. Tri Widjaja M.Eng.
Siti Nurkhamidah S.T., M.S, Ph.D


Nowadays, the world is facing fossil energy problems such as the rarity of petroleum and natural gas because these kinds of energy cannot be renewed. Therefore, the discovery of renewable energy source is very important to fulfil the world’s energy requirements that will always increase. Coffee pulp is one of the materials that can be used to produce glucose and xylose. The purpose of this study is to produce bioethanol from coffee pulp by utilized both cellulose and hemicellulose components. Coffee pulp is chosen because its production reached 743 kg/ha and has not been used properly. The compositions of coffee pulp are 63% cellulose; 2.3% hemicellulose; 17% lignin; 11.5% protein; 1.8 to 8.56% tannin and 6.5% pectin. Coffee pulp contains of high lignin, therefore pretreatment must be carried out to lower the lignin. Organosolv method is capable not only to produce large amount of high-quality and relatively pure lignin but also to dissolve most of the hemicellulose. The substrate of organosolv pretreatment has higher cellulose and hemicellulose contain than another alternative method. Alkaline method was used to compare the effectivity between alkaline and organosolv method. Cellulose and hemicellulose which are generated from chemical pretreatment, are being hydrolyzed using pure cellulase and xylene enzyme to be converted to glucose and xylose. Then, continue the hydrolysis to fermentation using variation of Saccharomyces cerevisiae, Zymomonas mobilismutant (A3) and Pichia stipitis to ferment xylose and glucose to be ethanol. From this research, we got the best pretreatment process that was shown in Organosolv …