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Aeration strategy: a need for very high ethanol performance in Saccharomyces cerevisiae fed-batch process
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Edité par CCSD ; Springer Verlag -
International audience. In order to identify an optimal aeration strategy for intensifying bio-fuel ethanol production in fermentation processes where growth and production have to be managed simultaneously, we quantified the effect of aeration conditions—oxygen limited vs non limited culture (micro-aerobic vs aerobic culture)—on the dynamic behaviour of Saccharomyces cerevisiae cultivated in very high ethanol performance fed-batch cultures. Fermentation parameters and kinetics were established within a range of ethanol concentrations (up to 147 g l−1), which very few studies have addressed. Higher ethanol titres (147 vs 131 g l−1 in 45 h) and average productivity (3.3 vs 2.6 g l−1 h−1) were obtained in cultures without oxygen limitation. Compared to micro-aerobic culture, full aeration led to a 23% increase in the viable cell mass as a result of the concomitant increase in growth rate and yield, with lower ethanol inhibition. The second beneficial effect of aeration was better management of by-product production, with production of glycerol, the main by-product, being strongly reduced from 12 to 4 g l−1. We demonstrate that aeration strategy is as much a determining factor as vitamin feeding (Alfenore et al. 2002) in very high ethanol performance (147 g l−1 in 45 h) in order to achieve a highly competitive dynamic process.
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