Hydrogen Production under Aerobic Conditions by Membrane-Bound Hydrogenases from Ralstonia Species
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- 作者：Gabrielle Goldet ; Annemarie F. Wait ; James A. Cracknell ; Kylie A. Vincent ; Marcus Ludwig ; Oliver Lenz ; Bä ; rbel Friedrich ; Fraser A. Armstrong
- 刊名：Journal of the American Chemical Society
- 出版年：2008
- 出版时间：August 20, 2008
- 年：2008
- 卷：130
- 期：33
- 页码：11106-11113
- 全文大小：304K
- 年卷期：v.130,no.33(August 20, 2008)
- ISSN：1520-5126
文摘
Studies have been carried out to establish the ability of O2-tolerant membrane-bound [NiFe] hydrogenases (MBH) from Ralstonia sp. to catalyze H2 production in addition to H2 oxidation. These hydrogenases are not noted for H2-evolution activity, and this is partly due to strong product inhibition. However, when adsorbed on a rotating disk graphite electrode the enzymes produce H2 efficiently, provided the H2 product is continuously removed by rapidly rotating the electrode and flowing N2 through the gastight electrochemical cell. Electrocatalytic H2 production proceeds with minimal overpotentiala significant observation because lowering the overpotential (the electrochemically responsive activation barrier) is seen as crucial in developing small-molecule catalysts for H2 production. A mutant having a high KM for H2 oxidation did not prove to be a better H2 producer relative to the wild type, thus suggesting that weak binding of H2 does not itself confer a tendency to be a H2 producer. Inhibition by H2 is much stronger than inhibition by CO and, most significantly, even O2. Consequently, H2 can be produced sustainably in the presence of O2 as long as the H2 is removed continuously, thereby proving the feasibility for biological H2 production in air.