CARBON SOURCES 121 



The explanation of this anomalous situation was given by Margolin 

 (1940) and confirmed by Wilson (1942), who found that D. macrospora 

 was deficient for biotin. It is probable that other vitamin-deficient 

 fungi have been reported in the past as unable to utilize certain sugars 

 owing to the absence of specific growth factors. Negative results 

 reported in the literature are therefore to be viewed with caution. 



Wolf and Shoup (1943) studied the oxidation of carbohydrates by 

 Allomyces arhuscula, A. javanicus, A. moniliformis, and A. cystogenus. 

 All four species oxidized dextrin (degraded starch), while A. arhuscula 

 oxidized maltose and sucrose in addition. The other common naturally 

 occurring sugars, including glucose and fructose, were not oxidized. It 

 has since been shown that A. arhuscula is deficient for methionine and 

 thiamine (Yaw, 1950). 



While there is an immense amount of information scattered throughout 

 the literature to the effect that a certain sugar is utilized by various 

 species, much of this information deals with relatively few sugars. 

 Critical studies on the utilization of the sugars are rare. Margolin 

 (1942) studied the amount of growth of 21 fungi on four hexoses. These 

 data (Table 22) were obtained under uniform conditions. A mixed 

 nitrogen source (ammonium nitrate and amino acids) was used, and 

 vitamins were supplied to the deficient fungi. The time chosen for 

 harvest in this study was the time maximum weight was attained on 

 glucose. This work suffers from the common defect that the yields are 

 compared on the basis of a fixed time of harvest. The ideal way of 

 determining the value of different sugars for fungi would be to study 

 both the rate and amount of growth as a function of time of incubation. 



The following generalizations about utilization of the common hexoses 

 may be drawn from the data in Table 22: (1) There is no single sugar 

 which supports the maximum amount of growth for all of these fungi. 

 (2) All of these fungi utilize glucose, although the maximum amount of 

 growth was not always attained on this sugar. (3) The more closely the 

 configuration of another sugar approaches that of glucose, the more 

 fungi utilize it. It is believed that these generalizations are valid for all 

 fungi which utilize sugars. 



Steinberg (1939) found D-glucose, D-fructose, D-mannose, L-sorbose, 

 and sucrose to be equally effective in the nutrition of Aspergillus niger 

 while D-galactose, lactose, glycerol, and mannitol were poor sources of 

 carbon for this fungus. Herrick (1940) reported that two isolates of 

 Stereum gausapatum grew on glucose, fructose, mannose, and galactose. 

 One isolate made significantly better growth on fructose; the other grew 

 equally well on all four sugars. This indicates that not all isolates of a 

 species are alike in ability to utilize a given sugar. The utilization of 

 different carbon sources by A. oryzae was investigated in detail by Tamiya 



