Methods of stimulating biogenic production of a metabolic product with enhanced hydrogen content are described. The methods may include accessing a consortium of microorganisms in a geologic formation that includes a carbonaceous material. They may also include providing hydrogen and one or more phosphorous compounds to the microorganisms. The combination of the hydrogen and phosphorous compounds stimulates the consortium to metabolize the carbonaceous material into the metabolic product with enhanced hydrogen content. Also, methods of stimulating biogenic production of a metabolic product with enhanced hydrogen content by providing a carboxylate compound, such as acetate, to a consortium of microorganisms is described. The carboxylate compound stimulates the consortium to metabolize carbonaceous material in the formation into the metabolic product with enhanced hydrogen content.