Figure 8. Oxidation of NADH to NAD⁺ coupled to H₂ generation on carbon particles.

(A) Thermodynamics for H₂ + NAD⁺ ↔ H⁺ + NADH at high and low H₂ partial pressures (pH₂) and a range of NAD⁺:NADH ratios. (B) Schematic representation of enzyme-modified particles for NADH oxidation and H₂ production. (C) Conversion of NADH to NAD⁺ using H⁺ reduction as the electron sink at carbon black particles modified with E. coli Hyd2 [18] and the NAD⁺-reducing HoxH^I64AYFU of R. eutropha in the presence of NADH (1 mM) at pH 8, 30°C.