Metabolism Peculiarities of Bacteria of the Genus Sulfobacillus
The genus Sulfobacillus includes moderately thermophilic and thermotolerant acidophilic bacteria, which prefer mixotrophic growth conditions. These organisms are S. thermosulfidooxidans 1269Т, S. sibiricus N1Т and S. thermotolerans Kr1Т. The simultaneous presence of organic (for example yeast extract) and inorganic energy sources is essential for optimal growth. Carbon sources are both CO2 and organic compounds. During their mixotrophic growth, the basic pathways of carbohydrate catabolism of sulfobacilli are those of glycolysis, oxidative pentose phosphate and Entner–Doudorov (excepting strain N1). Assimilation of CO2 is carried out both auto- and heterotrophically. Final stages of oxidation of organic substances serve for cell biosynthesis. Bacteria are able to switch to organo- and autotrophic metabolism. At that the enzyme activities of pentose phosphate pathway are not detected. The cycle of tricarboxylic acids is disrupted at the level of 2-oxoglutarate dehydrogenase. The glyoxylate bypass is absent. The maximal protein and ATP values and high intensity of respiration in S. thermosulfidooxidans, S. sibiricus and S. thermotolerans cultures were determined under mixotrophic conditions. Studied strains due to their flexible carbon and energetic metabolism together with other microorganisms of communities (leptospirilli and archaea) participate in sulfide minerals processing at 40-450C without organic compounds supplement.
Axel Schippers, Wolfgang Sand, Franz Glombitza and Sabine Willscher
A. E. Zhuravleva et al., "Metabolism Peculiarities of Bacteria of the Genus Sulfobacillus", Advanced Materials Research, Vols. 20-21, pp. 469-472, 2007