Deltaproteobacterium Strain KaireiS1, a Mesophilic, Hydrogen-Oxidizing and Sulfate-Reducing Bacterium From an Inactive Deep-Sea Hydrothermal Chimney

A novel deltaproteobacterial, mesophilic, hydrogen-oxidizing, and sulfate-reducing bacterium (strain KaireiS1) was highly enriched from an inactive chimney located in the active zone of Kairei hydrothermal vent field (Central Indian Ridge) Ocean. Based on 16S rRNA gene analyses, strain KaireiS1 is currently only cultured representative a cluster uncultured Deltaproteobacteria, positioned within Desulfobulbaceae family, between Desulfobulbus genus “Cable Bacteria.” facultative autotrophic lifestyle indicated by its growth absence organic compounds, measurements CO 2 -fixation rates, activity carbon monoxide dehydrogenase, key enzyme reductive Acetyl-CoA pathway. Apart hydrogen, can also use propionate, lactate, pentadecane as electron donors. However, highest cell numbers were reached when grown autotrophically with molecular hydrogen. Hydrogen uptake found membrane soluble fractions cell-free extracts up to 2,981±129 nmol H *min ?1 *mg partially purified protein. Commonly, bacteria Deltaproteobacteria class, thriving habitats are described thermophiles. Given physiological characteristics specific isolation source, demonstrates previously unnoticed potential for microbial sulfate reduction autotrophs taking place at moderate temperatures fields.