PRINCIPLES OF MICROBIAL METABOLISM 



381 



cells consisted of 10.9 per cent P 2 5 ; with 7.9 per cent P 2 5 in the 

 medium, the ash of the bacteria contained 28.7 per cent P2O5; with 

 39.8 per cent P 2 5 of the ash in the medium, the ash of the bacteria 

 consisted of 38.4 per cent P 2 5 . 34 The same is not true, however, of 

 the other ash constituents. Among these, we find K, Na, Mg, Ca, Fe, 

 Si, S and CI, 35 as shown in table 24. 



Some organisms (Aspergillus, Penicillium, Mucor and other fungi) 

 can thrive without calcium, while others (Azotobacter) do not develop 

 in the absence of this mineral element. 36 



According to Stoklasa, 37 Azot. chroococcum consists of 11.3 per cent 

 nitrogen (see p. 570) and 9.GG per cent ash. The latter is made up of 



TABLE 24 

 Mineral composition of microorganisms 



4.93 per cent P 2 5 , 0.29 per cent S0 3 , 2.41 per cent K 2 0, 0.07 per cent 

 Na 2 0, 0.82 per cent MgO, 0.34 per cent CaO and 0.08 per cent Fe 2 3 . 

 The non-nitrogenous portion of the microbial cell consists chiefly of 

 fats, gums and various hemicelluloses, chitin and frequently glycogen. 

 Winterstein and Reuter 38 reported that ether extracted from higher fungi 



34 See also de Rossi, 1925 (p. xiii). 



35 See also Mayer, A. Garungschemie. 5 Aufl. 1902, p. 118 (cited by Kruse). 



36 Loew, O. tJber das Kalkbedurfnis von Algen und Pilzen. Biol. Centrbl., 

 45: 122-125. 1925. 



37 Stoklasa, 1908 (p. 114). It will be shown later (p. 570) that analyses of 

 Azotobacter cells made by different investigators do not agree. 



38 Winterstein, E., and Reuter, C. tTber die stickstoffhaltigen Bestandteile 

 der Pilze. Centrbl. Bakt. II, 34: 566-572. 1912. See also N. L. Iwanow. 

 tTber die Natur des Eiweisstoffes der Pilze. Biochem. Ztschr., 137: 331-340. 



