376 



DANIEL I. ARNON 



PHOTO PRODUCTION OF H2 FROM THIOSULFATE 

 7 \ 1 1 1 1 r 



Fig. 18. Effect of pH on photoproduction of hydrogen gas from thiosulphate 

 by Chromatmm cells. Experimental conditions as described for Fig. 16. Phosphate 

 buffer was used at pH 6-5 and 7-0 and tris buffer at pH 7-5 and 80 (Losada, 

 Nozaki, and Arnon [136]). 



this period the appearance of the culture indicated a transitional formation 

 of elemental sulphur. The results are in agreement with the following 

 sequence of reactions, in which thiosulphate is the donor of electrons that 

 are activated by light and used either for the assimilation of carbon and 



10 20 30 40 50 60 

 minutes 



Fig. 19. Effect of No and NH4CI on photoproduction of H2 from thiosulphate 

 by Chromatiiini cells. Experimental conditions as described for Fig. 16. 5 /xmoles 

 NH4CI and No gas were used as indicated (Losada, Nozaki, and Arnon [136]). 



