Hydrogenase Activity of Mineral-Associated and Suspended Populations of Desulfovibrio desulfuricans Essex 6

• Published in: Microbial ecology Vol. 67; no. 2; pp. 318 - 326
• Main Authors: Reardon, C. L, Magnuson, T. S, Boyd, E. S, Leavitt, W. D, Reed, D. W, Geesey, G. G
• Format: Journal Article
• Language: English
• Published: New York Springer-Verlag 01.02.2014; Springer; Springer US; Springer Nature B.V
• Subjects: biochemical pathways; biofilm; Biofilms; biogeochemical; Biological and medical sciences; Biomedical and Life Sciences; Chemical suspensions; chlorine; Cultured cells; Desulfovibrio; Desulfovibrio desulfuricans; Desulfovibrio desulfuricans - enzymology; Desulfovibrio desulfuricans - isolation & purification; DNA, Bacterial - genetics; Ecology; electron transfer; ENVIRONMENTAL MICROBIOLOGY; Enzymes; fermentation; ferredoxin hydrogenase; Ferric Compounds - chemistry; ferric oxide; Fundamental and applied biological sciences. Psychology; Geoecology/Natural Processes; GEOSCIENCES; Hematite; hydrogen; Hydrogen - chemistry; hydrogenase; Hydrogenase - genetics; Hydrogenase - metabolism; iron; Iron - chemistry; iron oxides; Life Sciences; Microbial Ecology; Microbiology; microorganisms; Minerals; Minerals - chemistry; Nature Conservation; oxidation; Oxidation-Reduction; Polymerase chain reaction; pyruvic acid; Reverse transcriptase polymerase chain reaction; Sequence Analysis, DNA; sulfate-reducers; Sulfates; Sulfates - chemistry; Sulfides; Water Quality/Water Pollution; British Isles, England, Essex; Hematite; Greigite; Desulfovibrio; Hydrogenase Activity; Mackinawite; Hydrogenase; Desulfovibrio desulfuricans; Enzyme; Bacteria; Ecology; Oxidoreductases; Minerals
• ISSN: 0095-3628; 1432-184X
• DOI: 10.1007/s00248-013-0308-y

The interactions between sulfate-reducing microorganisms and iron oxides influence a number of important redox-sensitive biogeochemical processes including the formation of iron sulfides. Enzymes, such as hydrogenase which catalyze the reversible oxidation of molecular hydrogen, are known to mediate electron transfer to metals and may contribute to the formation and speciation of ferrous sulfides formed at the cell–mineral interface. In the present study, we compared the whole cell hydrogenase activity of Desulfovibrio desulfuricans strain Essex 6 growing as biofilms on hematite (hematite-associated) or as suspended populations using different metabolic pathways. Hematite-associated cells exhibited significantly greater hydrogenase activity than suspended populations during sulfate respiration but not during pyruvate fermentation. The enhanced activity of the hematite-associated, sulfate-grown cells appears to be dependent on iron availability rather than a general response to surface attachment since the activity of glass-associated cells did not differ from that of suspended populations. Hydrogenase activity of pyruvate-fermenting cells was stimulated by addition of iron as soluble Fe(II)Cl₂ and, in the absence of added iron, both sulfate-reducing and pyruvate-fermenting cells displayed similar rates of hydrogenase activity. These data suggest that iron exerts a stronger influence on whole cell hydrogenase activity than either metabolic pathway or mode of growth. The location of hydrogenase to the cell envelope and the enhanced activity at the hematite surface in sulfate-reducing cells may influence the redox conditions that control the species of iron sulfides on the mineral surface.