BIOETHANOL PRODUCTION FROM ARUNDO DONAX HYDROLYSATE USING CO-CULTURE OF PICHIA STIPITIS AND SACCHAROMYCES CEREVISIAE IN A STIRRED TANK BIOREACTOR

摘要

An efficient production of ethanol from lignocellulosic hydrolyzates requires the use ofmicroorganisms capable to convert both glucose and xylose sugars with high yields. One approach to achieve thistarget is the use of yeast co-cultures, formed by Pichia stipitis, renamed Scheffersomyces stipitis, and Saccharomycescerevisiae species, which are characterized by different metabolic activities. In this context, numerous parameters,such as temperature, pH and oxygen requirements are critical factors in the fermentation process and, among these,aeration is very important because of its influence on xylose conversion. In this work, ethanol production fromArundo Donax hydrolyzates was evaluated in a stirred tank bioreactor using co-cultures of Schef. stipitis and S.cerevisiae strains. Experimental tests were performed at different values of aeration, providing different volumetricoxygen transfer coefficient (KLa) and using activated charcoal to reduce the inhibitors toxic effect.