TRANSFORMATION OF MINERALS IN THE SOIL 



651 



In the presence of available carbon and nitrogen sources, microorgan- 

 isms will rapidly break down the lecithin and liberate the phosphorus. 

 A transformation of G6 per cent of the lecithin phosphorus into soluble 

 phosphate by different bacteria, in 60 days at 28° to 30°C, has been 

 reported; 17 the rest of the phosphorus was reassimilated by the bacteria. 



Phytin is an hexaphosphate, occurring abundantly in vegetable 

 tissues, especially in seeds or grains. 22 It contains (as phytic acid, 

 C 6 H 2 402 7 P6) about 26 per cent phosphorus. It is acted upon by fungi 

 and bacteria by means of an enzyme, phytase, 23 with the transforma- 

 tion of the phosphorus into the inorganic form. 



Nucleo-proteins contain 7 to 9 per cent phosphorus and 13 to 14 per 

 cent nitrogen. The resulting products of their decomposition are phos- 

 phoric acid, a sugar, purine and pyrimidine bases. 24 The nucleic acids 

 are broken down by various soil microorgansims, both in the presence 



and absence of other nitrogen sources. Koch and Oelsner 24 found that, 

 in addition to some common soil organisms, a special group of bacteria 

 (genus Nucleobacter) is specifically concerned in the decomposition 

 of nucleins, through the nucleic acid stage, into phosphoric acid. 



22 Anderson, R. J. Phytin and phosphoric acid esters of inosite. N. Y. 

 (Geneva) Agr. Exp. Sta. Tech. Bui. 19. 1912; The organic phosphoric acid of 

 cottonseed meal. Ibid., Bui. 25. 1912. 



23 Dox, A. W., and Golden, R. Phytase in lower fungi. Jour. Biol. Chem., 

 10: 183-186. 1911; Plimmer, R. H. A. The metabolism of organic phosphorus 

 compounds. Their hydrolysis by the action of enzymes. Biochem. Jour., 7: 

 43-71. 1913; Egorov, M. A. tlber das Verhalten von Schimmelpilzen (A. niger 

 und P. glaucum) zum Phytin. Ztschr. physiol. Chem., 82: 231-242. 1912. 



24 Iwanoff, N. Nuclease, forkommend in Schimmelpilzen. Ztschr. Garungs- 

 physiol., 1: 60. 1912; also Ztschr. physiol. Chem., 39: 31-43. 1903; Schitten- 

 helm, A., and Schroeter, F. Uber die Spaltung der Hefenukleinsaure durch 

 Bakterien. Ztschr. physiol. Chem., 39: 203-207. 1903; 40: 62-69. 1903; 41: 

 283-292. 1903; 57: 21-27. 1908; Koch, A., and Oelsner, A. Uber Nucleopro- 

 teidspaltende Bakterien und ihre Bedeutung fur die Erschliesung des Phosphor- 

 Kaptials im Ackerboden. Biochem. Ztschr., 134: 76-96. 1922. 



