MINERAL CONSTITUENTS 37 



Table 1. Major Constituents of Cultivated Fungi and Actinomycetes* 



Carbo- 

 Organism 



Aspergillus oryzae (spores) (171) 

 Gliocladium roseum (157) 

 Rhizopus japonicus (99) 

 Penicillium chrysogenum (157) 

 Penicillium griseojulvum (165) 

 Phymatotrichum omnivorum (42) 



* As per cent of dry weight. 



t Estimated from total nitrogen only. 



\ Estimated from total nitrogen after subtraction of chitin nitrogen. 



§ Determined in a chitin-free fraction. 



and differ in amount from one species to another. As discussed below, 

 those protein values of Table 1 which are based only on the total 

 nitrogen are almost certainly high. 



2. MINERAL CONSTITUENTS OF THE CELL 



The ash content of fungi varies with the medium used and, pre- 

 sumably, with species. Some figures reported for total ash as per cent 

 of dry weight are: Rhizopus japonicus, 5.52 (99); Aspergillus niger, 

 2.39 (129); A. oryzae, 7.19 (78); Coprinus radians, 4.97 (78); Penicil- 

 lium notatum, 28.3-34.0 (50). Fruiting bodies collected in the field 

 may be as low as 1.08 or as high as 29.8 per cent ash; most have 5-10 

 percent (197). 



The composition of the ash of a few fungi is summarized in Table 2. 

 Although no figures should be considered typical, it is clear that the 

 most abundant minerals are phosphorus and potassium. Probably 

 none of the analyses of Table 2 is complete, and inspection raises some 

 obvious problems, e.g., the accumulation of silicon in Rhizopus japoni- 

 cus and aluminum in Penicillium notatum. 



The total ash content and the concentration of individual elements 

 are influenced by the environment and by the stage of development. 

 In Aspergillus niger the total ash of conidia is about three times that 

 of mycelium; the increase is confined, however, to a few of the ele- 

 ments, particularly phosphorus, potassium, and magnesium (5, 139). 

 Autolysis is accompanied by loss of phosphorus (Gl) and by a decline 

 in total ash (100). Among the environmental effects, the simplest is 

 the increase in the internal concentration of an element in the my- 

 celium as its external concentration is raised (62, 139, 144, 164). The 

 total ash and the concentration of individual elements are also influ- 



