Evaluation of the potential hydrogen production by diazotrophic Burkholderia species

摘要

Hydrogen (H_2) is considered one of the most promising fuels for sustainable energy. Because nitrogenase produces H_2 as a normal by-product, we tested the N_2-fixing bacterial strains Burkholderia unamae and Burkholderia tropica to determine their H_2 production capacities. To maximize H_2 production, several culture conditions were tested and optimized, including atmospheric conditions, carbon sources and chemical compounds such as enzyme cofactors and sugar cane molasses. The results showed that both strains were capable of H_2 production. The culture medium with the highest H_2 yield was composed of 1% v/v molasses enriched with Na_2MoO_4 (0.2 g/L), FeSO_4 (0.2 g/L) and cysteine (0.02 g/L) under a partial vacuum (air 20% v/v) without Ar final atmosphere. Under these conditions, the highest H_2 production rate obtained was 24.64 mmol H_2/L for B. unamae. The present study contributes an optimization process for H_2 production in N_2-fixing Burfeholderia species. We propose further research and development to improve H_2 production rates in order to make biohydrogen a tangible reality.