Production of Bioethanol from Sugarcane Bagasse Using Saccharomyces Cerevisiae

Abstract

__________________________________________________________________________________ Abstract: An improvement in bioethanol production from glucose-xylose sugars has been achieved by a recombinant xylose fermenting Saccharomyces cerevisiae SK-NY. The recombinant strain was used to ferment sugars hydrolyzed from hemicellulose combined with enzymatically saccharified cellulose of sugarcane bagasse. The main components of bagasse were cellulose, hemicellulose, lignin and ash representing 37.3%, 30.5%, 30.2% and 1.99% of total weight respectively. Hemicellulose hydrolysis conditions were optimized by pretreatment of bagasse with 1% sulfuric acid at 135ºC for 25 min. Delignification was accomplished by three oxidation-bleaching cycles of treatment using sodium chlorite and acetic acid at 70 ºC for one hour per cycle. Liberation of integrated lignin takes place in the final oxidation cycle by the swelling action of sodium bicarbonate. Simultaneous saccharification of cellulignin and cellulose with cofermentation (SSCF) of sugars hydrolyzed from hemicellulose were compared using cellulase enzyme and recombinant S. cerevisiae SK.NY. Released glucose-xylose sugars were successfully fermented and the productivity of ethanol was raised from 13.7 g/l to 18.9 g/l from cellulignin and cellulose respectively. Enzymatic saccharification of cellulose showed 37% higher production of glucose compared with that produced from cellulignin. Consequently, the bioethanol production from sugar obtained by SSCF of cellulose increased to 28%.