Combet-Blanc Yannick, Dieng M.C., Kergoat P.Y. (1999). Effect of organic complex compounds on Bacillus thermoamylovorans growth and glucose fermentation. Applied and Environmental Microbiology, 65 (10), p. 4582-4585. ISSN 0099-2240.
Titre du document
Effect of organic complex compounds on Bacillus thermoamylovorans growth and glucose fermentation
Année de publication
1999
Type de document
Article
Auteurs
Combet-Blanc Yannick, Dieng M.C., Kergoat P.Y.
Source
Applied and Environmental Microbiology, 1999,
65 (10), p. 4582-4585 ISSN 0099-2240
The effect of the concentration of a mixture (1/1 (wt/wt)) of yeast extract and bioTrypcase (YE+bT) on the growth and physiology of a new species, Bacillus thermoamylovorans, a moderately thermophilic, non-spore-forming, lactic-acid producing bacterium isolated from palm wine, was studied. At an initial glucose concentration of 100mM, B. thermoamylovorans growth was limited when the concentration of YE+bT was lower than 5.0 g/l ; under these conditions, cellular yield reached a maximum value of 0.4 g of cells per g of YE+bT. Growth limitation due to deficiency in growth factors led to a significant shift in glucose metabolism towards lactate production. Lactate constituted 27.5 and 76% of the end products of glucose fermentation in media containing YE+bT at 20.0 and 1.0 g/l, respectively. This result markedly differed from published data for lactic bacteria, wich indicated that fermentative metabolism remained homolactic regardless of the concentration of YE. Our results showed that the ratio between cellular synthesis and energy production increased with the concentration of YE+bT in the culture medium. They indicate that the industrial production of lactic acid through glucose fermentation by B. thermoamylovorans can be optimized by using a medium where glucose is present in excess and the organic additives are limiting. (Résumé d'auteur)
