Growth parameters of Acinetobacter calcoaceticus on acetate and ethanol

Abstract

The growth parameters of Acinetobacter calcoaceticus, relevant to its mass cultivation on acetate and ethanol, were determined in batch and continuous culture experiments. Acetic acid exhibited a more powerful inhibitory effect on the growth rate than ethanol. In batch culture, the acetate component of an acetate-ethanol substrate pair was preferentially utilized, but diauxic growth as such was not evident. The temperature optimum for growth was in the region of 29°–36°C, and the cell yield did not change appreciably over this temperature range. In carbon-limited chemostat cultures, the maximum specific growth rates on acetate and ethanol were 1.22 h−1 and 0.96 h−1 respectively, and the respective yield coefficients were 0.4 and 0.75. A high maintenance energy requirement was exhibited, especially during acetate-limited growth. The respiratory quotient was dependent on the growth rate, the significance of which is discussed.