Carbon metabolism inSulfobacillus thermosulfidooxidans subsp.asporogenes, strain 41

Abstract

The activities of carbon metabolism enzymes were determined in cellular extracts of the moderately thermophilic, chemolithotrophic, acidophilic bacterium Sulfobacillus thermosulfidooxidans subsp. asporogenes, strain 41, grown either at an atmospheric content of CO2 in the gas phase (autotrophically, heterotrophically, or mixotrophically) or autotrophically at a CO2 content increased to 5-10%. Regardless of the growth conditions, all TCA cycle enzymes (except for 2-oxoglutarate dehydrogenase), one glyoxylate cycle enzyme (malate synthase), and some carboxylases (ribulose bisphosphate carboxylase, pyruvate carboxylase, and phosphoenolpyruvate carboxylase) were detected in the cellular extracts of strain 41. During autotrophic cultivation of strains 41 and 1269, the increase in the CO2 content of the supplied air to 5-10% resulted in the activation of growth and iron oxidation, a 20-30% increase in the cellular content of protein, enhanced activity of the key TCA enzymes (citrate synthase and aconitase), and, in strain 41, a decrease in the activity of carboxylases.