00 



CARBON METABOLISM I 



only 3 produced significant amounts of soluble carbon compounds. 

 The classical studies of Birkinshaw, Raistrick, and others were car- 

 ried out on common saprophytes growing in a medium relatively high 

 in carbohydrates; even under these conditions numerous species of 

 Penicillium, Aspergillus and other genera were found to form only 

 carbon dioxide and cell substance. It is safe also to assume that fungi 

 growing in soil do not accumulate the same products which they do 

 in pure culture. 



Carbon balance studies provide essential information as to the 

 type of metabolism involved. The methods of Birkinshaw and Rais- 

 trick (6) are still valuable, and others have been developed more re- 

 cently (18). Table 1 illustrates a typical carbon and oxidation-reduc- 

 tion balance. Determinations of carbon balances include many on 

 members of the Fungi Imperfecti (2, 4, 5, 12, 15, 20), and a few on 

 the lower phycomycetes (8, 13) and on the higher fungi (3, 18, 21). 



Table 1. Carbon and Oxidation-Reduction Balances in 

 Aspergillus Niger (18) 



Carbon recovery = 227.2/228.0 = 99.7% 

 Oxidation-reduction balance = 221.4/218.6 = 1.01 



* See original paper for calculation. 



f Per atom nitrogen. 



