156 PEOVisioN OF energy: oxidation 



In this case COg is utilised for cell synthesis, the energy- 

 being provided by fatty acid metabolism. However, in other 

 cases amongst the Clostridia, the CO2 can act as hydrogen 

 acceptor as well as a source of cell-carbon, e.g. Wieringa 

 isolated an organism from mud which reduces CO2 to acetic 

 acid in the presence of gaseous hydrogen as H-source : 



2CO2 + 4H2 -> CH3 . COOH + 2H2O. 



FOR FURTHER READING 



" Microbial Assimilations," Chfton, C. E., Advances in 

 Enzymology, 1946, 6, 269. 



" The Intermediate Stages in the Biological Oxidation of 

 Carbohydrate," Krebs, H. A., Advances in Enzymology, 

 1943, 3, 191. 



Papers : 



1. Bertrand, G., Ann. Chim. et Phys., 8, 181 (Acetobacter). 



2. Still, L., Biochem. J., 1940, 34, 1177 {Esch. coli). 



3. Barker, H. A., J. Biol. Chem., 1941, 137, 153 {Methano- 

 hacter). 



