GROWTH YIELD OF AN ORANGE-COLORED STREPTOCOCCUS BOVIS NO. 148

Abstract

The growth yield of orange-colored Streptococcus bovis No. 148 isolated from bovine rumen was investigated. The high growth yield of S. bovis occurred in the presence of CO₂ under batch culture conditions, and the maximum value for Y_ATP (the gram dry weight of organism produced per mol of ATP) was about 18. The growth yield was decreased by the addition of NaHCO₃ or Na₂CO₃ which are commonly used as neutralizing agents for the culture of ordinary rumen bacteria. The growth-promoting effect of CO₂ could be partially replaced by some unsaturated fatty acids and oleate-containing compounds. It is suggested that lipid synthesis from CO₂ may be a rate-limiting step in the growth of S. bovis.