Enzymatic production of biohydrogen

Abstract

Although in theory the amount of hydrogen that could be generated from renewable sources of energy such as cellulose (a polymer of glucose) is vast¹, only 16–24% of the maximum stoichiometric yield of hydrogen from glucose (about 12 mol H₂ per mol glucose) is typically achieved by biological methods². Here we show that the enzymes of the oxidative pentose phosphate cycle^3,4,5 can be coupled to hydrogenase purified from the bacterium Pyrococcus furiosus, one of only a few hydrogenases that use NADP⁺ as the electron carrier⁶, to generate 11.6 mol H₂ per mol glucose-6-phosphate. Hydrogen produced by this pathway is the major product, unlike that produced by intermediate metabolic pathways of bacterial fermentation, and therefore has important practical implications for biohydrogen production⁷.