Aeration strategy: a need for very high ethanol performance in Saccharomyces cerevisiae fed-batch process

• Published in: Applied microbiology and biotechnology 2004-05, Vol.63 (5), p.537-542
• Main Authors: ALFENORE, S, CAMELEYRE, X, BENBADIS, L, BIDEAUX, C, URIBELARREA, J.-L, GOMA, G, MOLINA-JOUVE, C, GUILLOUET, S. E
• Format: Article
• Language: English
• Subjects: Aeration; Aerobiosis; Air; Biofuel production; Biological and medical sciences; Biomass; Bioreactors; Biotechnology; Culture Media; Energy; Ethanol; Ethanol - analysis; Ethanol - metabolism; Fermentation; Fundamental and applied biological sciences. Psychology; Glucose - metabolism; Glycerol - metabolism; Industrial applications and implications. Economical aspects; Industrial Microbiology - methods; Kinetics; Life Sciences; Oxygen Consumption; Saccharomyces cerevisiae; Saccharomyces cerevisiae - growth & development; Saccharomyces cerevisiae - metabolism; Time Factors; Vitamins - pharmacology; Yeast
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-003-1393-5

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.