Hiroe Yoshii

Biochemical Effects of Fatty Acid and its Derivatives on L-Glutamin Acid Fermentation:Part III. Biotin-Tween 60 Relationship in the Accumu-lation of L-Glutamin Acid and the Growth of Brevibacterium lactofermentum

Tween 60 (polyoxyethylene sorbitan monostearate) has been found to be the most effective derivative of fatty acid in accumulating l-glutamic acid in biotin-sufficient medium. The effect was exceedingly subject to the influence of the addition time of the ester, and this was observed also on the growth curve of Brev. lactofermentum. Changes of the growth curve caused by the varied addition time of the ester corresponded to those by the concentration of biotin in the medium that did not contain Tween 60. The patterns of fermentation course in the two corresponding conditions, such as biotin 3 μg/l and biotin 20 μg/l-Tween 60 mg/ml, agreed closely with each other. It seemed that identical cells were grown on the conditions. The only difference between the cells was observed as to the contents of intracellular biotin. Although l-glutamic acid was not accumulated by biotin-sufficient cells, cells with sufficient biotin and capable of accumulating l-glutamic acid were obtained in the presence of Tween 60, in wh...

Stimulatory effect of glycine betaine on l-lysine fermentation

SummaryThe growth rate, sugar consumption rate, and production rate of an l-lysine producing Brevibacterium lactofermentum mutant were stimulated by addition of exogenous glycine betaine. Glycine betaine stimulated the growth rate especially in media of inhibitory osmotic stress, and the stimulation was independent of any specific solute. Therefore growth stimulation by glycine betaine was considered to be an osmoprotective effect. A strong enhancement of the sugar consumption rate and the l-lysine production rate was observed even with resting cells under osmotic stress as well as in a fermentation with growing cells. These data indicated that the osmoprotective effects of glycine betaine on l-lysine production can be independent of protein synthesis.

Effect of glycine betaine on the sucrose catabolism of an l-lysine producing mutant of Brevibacterium lactofermentum

SummaryEffect of exogenous betaine on the growth of an l-lysine-producing mutant of Brevibacterium lactofermentum was examined in a medium containing different carbon sources such as glucose, fructose, or sucrose. The growth rate decreased significantly with a rise in temperature when sucrose was the carbon source. Both the specific sucrose consumption rate and the invertase activity of the mutant decreased with the culture period when the cultivation temperature was 35°C. The addition of betaine restored both growth and invertase activity on medium containing sucrose as the carbon source at 35°C. Betaine protected the invertase activity against the inactivating effects of high temperature in vitro. Furthermore, the addition of exogenous invertase into production medium at 35°C restored the growth rate to that at 32°C. These results indicated that growth decreased on medium containing sucrose at 35°C due to a decrease in invertase activity, and that addition of betaine was an effective way to enhance growth on this medium at a higher temperature.