Abstract: The present application provides a process for sequestering carbon dioxide to produce a biomass containing reaction product, the process comprising the steps of: I. contacting a raw carbon dioxide-containing feedstock with an absorption or dissolution medium to form a reagent stream comprising dissolved or absorbed inorganic carbon at least in the form of HCO3- and CO32- wherein the HCO3- :CO32- molar ratio in the reagent stream is at least about 0.8; II. contacting at least a portion of the reagent stream with a microbial broth in a bioreactor to produce a biomass-containing reaction product; III. separating the biomass-containing reaction product into a biomass product and a liquid stream; and IV. recycling at least a portion of the liquid stream to step i. of the process for use as, or as part of, the absorption or dissolution medium, wherein the pH of the absorption or dissolution medium is controlled to maintain the HCO3- :CO32- molar ratio in the reagent stream at least about 0.8.

Abstract: The present invention provides a process for the microbiological production of hydrogen from a hydrocarbon-rich deposit, said process comprising the step of modifying the composition of the deposit by the introduction into the deposit of at least one non-native hydrogen producing microorganism selected positively to diversify the microbiological abundance of hydrogen-producing microorganisms in the deposit and for the preferential production of hydrogen over methane.