Formate metabolism in sulfate reducing bacteria

Dissertation presented to obtain the Ph.D degree in Biochemistry

Sulfate reduction is a very ancient metabolic process and it is responsible for more than 50% of carbon mineralization in anaerobic marine sediments. Sulfate-reducing organisms (SRO) are able to couple the reduction of sulfate to the oxidation of organic compounds, such as lactate or formate, or molecular hydrogen (H2), in order to obtain energy for cell synthesis and growth. Despite recent significant advances, a lot remains to be known about the mechanisms for energy conservation in SRO, and the specific components involved in those mechanisms. Formate and hydrogen are two abundant metabolites in SRO habitats, usually formed as fermentation products of other organisms. However, while the role of hydrogen and hydrogenases in anaerobic metabolism has been intensively studied over the years, formate has not received the same attention as an equally important metabolite.(...)

The work presented in this thesis was financially supported by a PhD fellowship (SFRH/BD/24312/2005) awarded by Fundação para Ciência e Tecnologia (FCT).