Fermentative hydrogen production by microbial consortium

Heat pre-treatment of the inoculum associated to the pH control was applied to select hydrogen-producing bacteria and endospores-forming bacteria. The source of inoculum to the heat pre-treatment was from a UASB reactor used in the slaughterhouse waste treatment. The molecular biology analyses indicated that the microbial consortium presented microorganisms affiliated with Enterobacter cloacae (97% and 98%), Clostridium sp. (98%) and Clostridium acetobutyricum (96%), recognized as H₂ and volatile acids' producers. The following assays were carried out in batch reactors in order to verify the efficiencies of sucrose conversion to H₂ by the microbial consortium: (1) 630.0 mg sucrose/L, (2) 1184.0 mg sucrose/L, (3) 1816.0 mg sucrose/L and (4) 4128.0 mg sucrose/L. The subsequent yields were obtained as follows: 15% (1.2 mol H₂/mol sucrose), 20% (1.6 mol H₂/mol sucrose), 15% (1.2 mol H₂/mol sucrose) and 4% (0.3 mol H₂/mol sucrose), respectively. The intermediary products were acetic acid, butyric acid, methanol and ethanol in all of the anaerobic reactors.