Tolerance of Butyrivibrio fibrisolvens, a ruminal bacterium, to low pH
2004
Ohkawara, S. (Meiji Univ., Kawasaki, Kanagawa (Japan). Faculty of Agriculture) | Furuya, H. | Asanuma, N. | Hino, T.
Tolerance of Butyrivibrio fibrisolvens to low pH was examined. The results obtained with five strains showed that the lowest pH permitting growth was considerably different among strains (pH 5.2-6.0). In general, strains that showed higher acid tolerance had higher specific activity (enzyme content in cell) of H+-ATPase, and higher ability to increase the specific activity of H+-ATPase in response to low extraceller pH (pHe). Strains that showed higher acid tolerance had generally higher ability to produce lactate. Composition of membrane phospholipid and fatty acid composition of membrane phospholipid were greatly different among strains, and some strains appeared to alter the compositions in response to low pHe. However, the ability of B. fibrisolvens to regulate the composition of membrane lipid did not appear to be high. These results suggest that H+-ATPase is important for acid tolerance in B. fibrisolvens. However, a strain that showed acid tolerance had low specific activity of H+-ATPase, suggesting that this strain has other mechanism for acid tolerance.
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