534 



LIGHT AND LIFE 



PHOTOPRODUCTION OF H2 FROM SUCCINATE 



m/nufes 

 a. Photoproduction of hydrogen gas from succinate by Chromatium cells. 



Fig. 15 



Experimental conditions as described in Table 8 

 115). 



(Ogata, Nozaki, and Arnon, 



Investigations of cell-free hydrogenase preparations from photo- 

 synthetic bacteria have begun only recently. The hydrogenase of 

 R. nibrum, in a cell-free state, reduced certain dyes such as methylene 

 blue with H2, but the enzyme was incapable of reducing one-electron 



TABLE 8 



Photoproduction of Hydrogen from Succinate by Chromatium 



(Ogata, Nozaki, and Arnon, 115) 



Treatment 



1 . Complete 



2. Complete, KOH omitted 



3. Complete, dark 



4. Complete, succinate omitted 



1. Complete 



2. Complete, succinate omitted 



3. Complete, plus palladium asbestos 



4. Complete, plus carbon monoxide 



jumoles H2 

 evolved 



8.6 

 8.2 

 1.5 

 0.6 



5.9 



0.7 



0.3 



-0.7 



The complete system contained, in a final volume of 3.0 ml, 100 mg wet cells that 

 were suspended in a modified nutrient solution with nitrogen omitted, and the following 

 in micromolcs: Tris buffer, />H 7.2, 80; MgCl2, 5; succinate, 20. 0.1 ml of 20% KOH 

 was present in the center well. The reaction was carried out for 2 hours at 30°C in 

 argon. Illumination 35,000 Lux. 



