%0 Journal Article %A JUSTIN, PAULINE %A KELLY, D. P. %T Metabolic Changes in Thiobacillus denitrificans Accompanying the Transition from Aerobic to Anaerobic Growth in Continuous Chemostat Culture %D 1978 %J Microbiology, %V 107 %N 1 %P 131-137 %@ 1465-2080 %R https://doi.org/10.1099/00221287-107-1-131 %I Microbiology Society, %X Thiobacillus denitrificans grew exclusively aerobically in thiosulphate-limited chemostat culture at all dissolved oxygen concentrations between 12 and 216 μ m. Nitrate reduction did not occur in aerobic cultures and nitrate and nitrite reductases only reached high levels under complete anaerobiosis. Growth yield was greatest [11.50 g dry wt (mol thiosulphate oxidized)–1] at the lowest dissolved oxygen concentration (12 μ m) and decreased at higher dissolved oxygen concentrations, indicating oxygen to be a growth-inhibitory substrate; the anaerobic yield was only 77 % of the maximum aerobic yield (all tested at a dilution rate of 0.08 h–1) in agreement with thermodynamic calculations. Low activities of thiosulphate-oxidizing enzyme and sulphur-oxidizing enzyme were detected in aerobic cultures, but activities were even lower in anaerobic cultures. Efficient energy coupling mechanisms with respect to sulphur and thiosulphate oxidations are indicated. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-107-1-131