초록
In this study the effect of different buffering agents, pH control and N<SUB>2</SUB> sparging on biohydrogen production in Thermobrachium celere was investigated in batch cultivations. Among the tested buffers, none was able to prevent the medium acidification resulting in a premature interruption of the hydrogen production. Controlling the pH helped to sustain the growth, the complete substrate consumption and the H<SUB>2</SUB> production. However, in these conditions the increase of H<SUB>2</SUB> partial pressure induced a partial metabolic shift towards ethanol production resulting in a decreased H<SUB>2</SUB> yield. Analysis of formate accumulation during growth suggests that this compound might play a relevant role in the anabolic routes in T. celere. When frequent N<SUB>2</SUB> sparging was applied for H<SUB>2</SUB> removal, together with pH control, the H<SUB>2</SUB> yield was remarkably enhanced from 2.26 to 3.53 mol H<SUB>2</SUB>/mol glucose, and the maximum H<SUB>2</SUB> production rate and specific H<SUB>2</SUB> production rate reached 41.5 mmol H<SUB>2</SUB>/l/h and 142.3 mmol H<SUB>2</SUB>/h/g, respectively. This result suggests that under proper conditions T. celere is able to produce hydrogen at high yield and production rate.