Metals addition for enhanced hydrogen, acetic and butyric acids production from cellulosic substrates by Clostridium butyricum

This is the authors' abstract. We don't add key points for this paper.

The influence of Fe (Iron), Ni (Nickel) and Se (Selene), important cofactors for hydrogenase (hyd), was evaluated in the bioproduction of H2, volatile organic acids (VOA) and alcohols using Clostridium butyricum as inoculum and 5 g/L of cellulose, glucose or sugarcane bagasse (SCB) in batch reactors at 37 °C. Conditions A (25 μM Fe), B (25 μM Fe + 1 μM Ni), C (25 μM Fe + 1 μM Ni + 1 μM Se) and D (with no metal addition) using cellulose and glucose were performed to optimize the culture medium. H2 production was favored in condition A being around 16 mmol/L and 6 mmol/L for glucose and cellulose, respectively. The predominance of butyric acid was observed in all experimental series with cellulose and glucose. On the other hand, acetic acid was predominant in the SCB assay. The presence of other bacteria in SCB may have contributed to the change in the route of the final metabolites. The results suggested the possibility of improving H2 and OA production by C. butyricum supplementing the medium with Fe using SCB as substrate source.