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Multi-stage Continuous Culture Fermentation of Glucose-Xylose Mixtures to Fuel Ethanol using Genetically Engineered Saccharomyces cerevisiae 424A
Citation:
Govindaswamy, S. AND L. M. VANE. Multi-stage Continuous Culture Fermentation of Glucose-Xylose Mixtures to Fuel Ethanol using Genetically Engineered Saccharomyces cerevisiae 424A . Bioresource Technology. Elsevier Online, New York, NY, 101(4):1277-1284, (2010).
Impact/Purpose:
To inform the public
Description:
Multi-stage continuous (chemostat) culture fermentation (MCCF) with variable fermentor volumes was carried out to study utilizing glucose and xylose for ethanol production by means of mixed sugar fermentation (MSF). Variable fermentor volumes were used to enable enhanced sugar use, accounting for differences in glucose and xylose utilization rates. Saccharomyces cerevisiae 424A-LNH-ST was used for fermentation of glucose-xylose mixtures. The dilution rates employed for continuous fermentation were based on earlier batch kinetic studies of ethanol production and sugar utilization. With a feed containing circa 30 g L−1 glucose and 15 g L−1 xylose, cell washout was viewed at a dilution rate of 0.8 hr−1. At dilution rates below 0.5 hr−1, complete glucose use was observed. Xylose consumption in the first-stage 1 L reactor was only 37% at the lowest dilution rate studied, 0.05 hr−1. At this same flow rate, xylose consumption rose to 69% after subsequently passing through 3 L and 1 L reactors in series, mainly due to the longer residence time in the 3 L reactor (0.0167 hr−1 dilution rate).
