ENERGY TRANSFORMATION 415 



According to Aubel, 60 glucose is decomposed under anaerobic condi- 

 tions by Bad. coli by a reaction of internal coupling, one half molecule 

 (lactic acid) giving an exothermic reaction and the other half molecule 

 (pyruvic acid, used as a starting point for synthetic processes) giving 

 an endothermic reaction: 



C 6 H 12 6 = CH,.CHOH.COOH + CH 3 -COCOOH + H 2 



0.48 gram of carbon of the sugar decomposed gave 0.216 gram as lactic 

 acid, 0.081 gram as pyruvic acid, 0.042 gram as acetic acid, 0.044 gram 

 as alcohol, and 0.052 gram as C0 2 . From the point of view of energy 

 utilization, "aerobiosis" and "anaerobiosis" mean simply the liberation 

 of energy by free oxygen or by an intramolecular rearrangement. 



The transformation of urea into ammonium carbonate is a purely 

 hydrolytic process, which yields a small amount of energy. 61 



NH 2 CONH 2 + 2 H 2 = (NH 4 ) 2 C0 3 + 7 Cal. 



Efficiency of energy utilization by heterotrophic microorganisms. When 

 the various microorganisms are compared in the amount of nutrients 

 transformed and in the synthesis of cellular material, fungi are found 

 to consume, under favorable conditions, 1| to 2 times as much nu- 

 trient as is necessary for the building of the cells. Raulin, 62 for example, 

 found that A. niger will synthesize 1 gram of mycelium for every 

 2.30 grams of sugar decomposed, i.e., the coefficient of utilization of 

 sugar by this organism was 44 per cent. According to Wehmer, 63 the 

 growth of A. niger (weight of mycelium) is parallel to the energy value 

 of the nutrient. This is clearly illustrated in table 27. 64 Peptone is 

 the exception. This is probably due to the fact that a large part of 

 the energy was left unutilized in the form of protein-split products. Ter- 

 roine 55 has also shown that while 100 Cal. in the form of glucose will 



60 Aubel, E. Sur l'origine de l'energie permettant au Bacterium coli, de se 

 deVelopper aux depens du glucose. Compt. Rend. Acad. Sci., 181: 571-573. 

 1925. 



61 Berthelot, M., and Petit, P. Sur la chaleur animale et sur les chaleurs de 

 formation et de combustion de l'ur6e. Ann. chim. Phys. (6), 20: 13-20. 1890. 



62 Raulin, J. Etudes chimiques sur la vegetation. Ann. Sci. Nat. Bot. (5), 

 11: 93. 1869. 



63 Wehmer, C. Entstehung und physiologische Bedeutung der Oxalsaure ini 

 Stoffwechsel einiger Pilze. Bot. Ztg., 41: 337. 1891. 



"Kruse, 1910 (p. xii). 



"Terroine, Bonnet, Jacquot, and Vincent. 1923-1924 (p. 410). Bull. Soc. 

 Chim. Biol., 7: 351-379. 1925; Terroine, E. F., and Wurmser, P. L'utilisation 

 des substances ternaires dans la croissances de V Aspergillus niger. Compt. Rend. 

 Acad. Sci., 174: 1435-7. 1922; 175: 228-230. 



