On Indigo -fermentation'). 



Proceedings of the Section of Sciences, Kon. Akademie van Wetenschappen, .\nisttr- 

 dam, Vol. II, 1900, blz. 495 — 512. — Verscheen onder den titel vlndino-fermentatie' in 

 Verslagen Kon. Akademie van Wetenschappen, Wis-en Xatuurk. Aid., Amsterdam, 



Deel VIII, 1900, blz. 57.2-590. 



At a former occasion it was demonstrated -) that the indigo-plants may ue 

 brought to two physiologicallv different groups, viz. indo.xyl-plants, to which 

 the woad (Isaiis iiuctoria) belongs and indican-plants. Of the Jatter, which seem the 

 most numerously represented, were examined Indigofera leptostachya, Polygonum 

 tinctorium and Phaj'us grandiüorus^'). The result was that they contain specific en- 

 zymes differing from one another, which split the indican into indoxyl and glucose, 

 while in woad there is no such enzyme. Indican can moreover be decomposed by 

 katabolism *), i. e. by the direct action of the living protoplasm, which has been ob- 

 served in some indicanplants, beside enzyme-action. Various microbes, too, can de- 

 compose indican and here the decomposition is generally effected by katabolism 

 only; some species, however, contain specific indigo-enzymes. Hence the word sindigo- 

 fermentation« means two quite different processes: a katabolic and an enzymatic 

 process, and the enzymes are of twofold origin, products of higher plants and pro- 

 ducts of microbes. It is clear that in the formation of indigo from woad, in which no 

 glucoside but free indoxyl occurs, there can be no question of »indigo-fermentation«. 



I. Preparation of the Indican as used for the Experiments'"). 



For the preparation of indican-solutions from indican-plants, a method was de- 

 scribed (1. c. p. 122) the principle of which is so quickly to destroy the enzyme that 

 the glucoside can be dissolved without decomposition *). This is best done for Indigo- 

 fera and Polygonum by immersion in boiling water, by which an extraxt is obtained 



') I am indebted to Mr. T. F. B. van Hasselt and Mr. A. van Del den for assistance 

 in the foUowing studj-. 



-) >On Indigo-formation fmm the Woad (Isatis tinctoria)<. Proc. Royal Acad. of 

 Sciences. Amsterdam, Sept. 30, 1899, p. 120. 



') Received under this name from a horticultural institution. 



*) For this expression see: Centralbl. f. Bacteriologie 2e Abt. Bd. 6. p. 5, 1900. 



') Further informations about the indican and the enzj'me of Indigofera are found 

 in the recently published interesting paper of Mr. J. J. Hazewinkel, Maandelijksch 

 Bulletin van het Proefstation voor Indigo. Klaten (Java), .\flevering 1. Januari 1000, 

 Samarang. 



"■) For the prnduction of many other glucosides the same method can be applied. 



M. W. Beijerinck, Verzamelde Geschriften; Derde Deel. 



22 



