i86 Nutrition and Tannase Production 



vated on starch paste these developed the enzyme diastase; but if the 

 starch were replaced by meat extract no diastase was formed. Fermi* found 

 that of ten bacterial organisms, which developed the tryptio ferment in the 

 presence of peptones or albumen, none developed the enzyme on a sugar- ^ 

 containing nutrient solution. Wortman's' observations established the" 

 fact that the addition of tartaric acid prevented the formation of diastase 

 in bacteria which inhabited decaying potatoes. Fermi and Montesano's< 

 investigations indicated that the presence of sugar is not absolutely neces- 

 sary for the formation of the enzyme invertase. Various other investi- 

 gators have studied the influence of nutrition on the formation of enzymes 

 in bacteria. 



Dubourg* stated that a yeast which did not normally possess the invert- 

 ing enzyme was capable of developing it by proper cultivation. As a cul- 

 ture solution in the latter case, yeast water was used, to which was added S 

 per cent cane sugar and 5 per cent grape sugar. The yeast, after cultivation, 

 was thoroughly washed and then transferred to a cane sugar solution. 

 In the latter inversion occurred. The form of yeast was not an identified 

 strain. He reported that he was also able to develop the enzyme which 

 fermented galactose by similar methods. 



Klocker,^ employing the methods of Dubourg, was unable to develop 

 invertase in Saccharomyces apiculatus or maltase in Saccharomyces marxi- 

 anus which organisms do not normally possess these enzymes. The ability 

 to form specific enzymes, according to Klocker, is therefore a constant char- 

 acter of the yeast organism. 



Recently Harden and Norris' "have trained" the yeast Saccharomyces 

 Carlsherg I to ferment galactose by cultivating the yeast on hydrolyzed lac- 

 tose in yeast water to which was added 0.15 per cent of monobasic potassium 

 phosphate. Normally galactose is not fermentable by the above men- 

 tioned yeast. According to Kohl' the chemical nature of the solution and 

 the aeration of the culture influence the amount or activity of the enzyme 

 formed in the yeast organism, while the temperature of storage of the yeast 

 also markedly affects the enzyme content. 



- Claudio Fermi: Weitere Untersuchungen uber tryptischen Enzyme 

 der Mikroorganismen, Centralbl.f. Bad., x, pp. 401^08, 1891. 



' J. Wortman: Untersuchungen uber das diastatische Ferment der Bac- 

 terien, Zeiischr. f. physiol. Chem., vi, p. 287, 1882. 



^ C. Fermi and C. Montesano: Die von den Mikroben bedingte Inver- 

 sion des Rohrzuckers, Centralbl.f. Bad., i, Abt. II, pp. 482-87, 542-56. 



5 E. Dubourg: De la fermentation des saccharides, Compt. rend, de I' Acad, 

 des Sci., cxxviii, pp. 440-42. 



«Alb. Klocker: 1st die Enzymebildung bei der Alcoholgarungspilzen 

 ein verwertbares Artmerkmal?, Centralbl. f. Bad., vi, Abt. II, pp. 241- 

 45, 1900. 



' A. Harden and R. V. Norris: The Fermentation of Galactose by Yeast 

 and Yeast Juice, Proc. Roy. Soc, Ixxxii, B, pp. 645-49, 1910. 



8 F. G. Kohl : Die Hefpilze, 1908, pp. 79-81. 



