Biohydrogen production in alkalithermophilic conditions: Thermobrachium celere as a case study

In the present work the hydrogenesis in the anaerobic alkalithermophilic bacterium Thermobrachium celere was studied. The impact of several factors on hydrogen production during glucose fermentation was investigated in batch conditions. The optimal hydrogen production occurred at pH67 °C 8.2 with phosphate buffer concentration of 50 mM. Hydrogen yield reached the highest value of 3.36 mol H2/mol glucose when the partial pressure in the gas headspace was reduced. Supplementation of nitrogen sources and iron affected hydrogen production. Under optimized conditions, the maximum H2 accumulation and H2 production rate were estimated to be respectively 124.3 mmol H2/l culture and 20.7 mmol H2/l/h. Considering the efficient and rapid hydrogen evolution, and the ability to grow in extreme environments, T. celere might be a good candidate for biohydrogen production in open (non-sterile) bioprocess system.

Research highlights
► Hydrogen production in the alkalithermophile Thermobrachium celere was studied.
► Influence of chemo-physical parameters on H2 production during glucose fermentation.
► Medium composition and pH affected the hydrogen production.
► A yield of 3.36 mol H2/mol glucose was achieved at low hydrogen partial pressure.
► In optimal condition T. celere reached a hydrogen production rate of 20.7 mmol H2/l/h.