Inoculum pre-treatment affects the fermentative activity of hydrogen-producing communities in the presence of 5-hydroxymethylfurfural

Identification of Hydrogen Gas Producing Anaerobic Bacteria Isolated from Sago Industrial Effluent

In this study, the biohydrogen production ability of isolated strains with sago industrial effluent in anaerobic batch fermentation was investigated. The bacteria responsible for the biohydrogen were isolated and identified as Clostridium sartagoforme NASGE 01 and Enterobacter cloacae NASGE 02. The volume of biohydrogen gas generated from the effluent was determined by gas chromatography (GC) and the organic acids formed during the biohydrogen production were determined by GC equipped with a flame ionization detector (GC-FID). In batch fermentation, C. sartagoforme NASGE 01 produced high amount of biogas (232 ± 11.02 mL/L) and biohydrogen (41.5%) followed by E. cloacae NASGE 02 produced 212.8 ± 8 mL/L biogas containing 31.5% of biohydrogen. Moreover, the hydrogen production potential (P), production rate (Rm) and lag time (λ) were analyzed from Gompertz non-linear curve fit model. The peak hydrogen yield was obtained with C. sartagoforme NASGE 01 was 158.7 mL/g glucose (1.26 mol H₂/mol glucose) with the substrate degradation of 56.7%. Butyric acid was the major organic acid formed while hydrogen production with Clostridium sartagoforme NASGE 01 (176.4 mg/L) and Enterobacter cloacae NASGE 02 (285.1 mg/L). These experimental data demonstrated the feasibility of biohydrogen production using pure culture of anaerobic bacteria with sago industrial waste water as substrate.

Hydrogen production profiles using furans in microbial electrolysis cells

Microbial electrochemical cells including microbial fuel cells (MFCs) and microbial electrolysis cells (MECs) are novel biotechnological tools that can convert organic substances in wastewater or biomass into electricity or hydrogen. Electroactive microbial biofilms used in this technology have ability to transfer electrons from organic compounds to anodes. Evaluation of biofilm formation on anode is crucial for enhancing our understanding of hydrogen generation in terms of substrate utilization by microorganisms. In this study, furfural and hydroxymethylfurfural (HMF) were analyzed for hydrogen generation using single chamber membrane-free MECs (17 mL), and anode biofilms were also examined. MECs were inoculated with mixed bacterial culture enriched using chloroethane sulphonate. Hydrogen was succesfully produced in the presence of HMF, but not furfural. MECs generated similar current densities (5.9 and 6 mA/cm² furfural and HMF, respectively). Biofilm samples obtained on the 24th and 40th day of cultivation using aromatic compounds were evaluated by using epi-fluorescent microscope. Our results show a correlation between biofilm density and hydrogen generation in single chamber MECs.