Figure 8: The glyoxylate and dicarboxylate metabolism pathway. The formate dehydrogenase gene (EC: with 28 reads was identified in the wastewater sample but not detected in the activated sludge metagenome. Methanogenic archaea uses formate dehydrogenase gene in methane metabolism pathway to mineralize the intermediate mixture of formate, hydrogen, and acetate to methane and carbon dioxide.