3 66 CHEMICAL ACTIVITY OF ASPERGILLACE^. 



Asp. oryzce, secretes cytase (cellulase) ; but as the walls of the 

 barley endospore, which were treated (by Newcombe at least) 

 with the enzyme mixture from Asp. oryzm (the so-called " Taka- 

 diastase") consist merely of a hemicellulose (Reinitzer) attackable 

 even by malt amylase, this result is not decisive. In this case 

 the walls were dissolved even before the starch (in twenty-four 

 hours as compared with about eight to twelve days). OPPEN- 

 HEIMER (III.) regards this case as one of cellulose solution, and 

 (as reported by Miyoshi) has obtained the same effect with Fenic. 

 glmwcwm ; but Miyoshi found precisely the opposite. Yan Iterson 

 seems to have observed a very feeble action effected by Asp. niger 

 on blotting-paper. 



The fermentation of tannin, which was also considered to be a 

 glucoside, was reported by VAN TIEGHEM (XIII.), in 1867, to be 

 effected by two mould fungi, Asp. niger and Penic. glaucum. This 

 worker considered that the fission of tannin into gallic acid and 

 glucose was a " true fermentation phenomenon," i.e., a manifesta- 

 tion of vital activity, and not the effect of a substance secreted 

 by the mycelium of the fungus. FERNBACH (III.) and POTTEVIN 

 (II.) afterwards demonstrated contemporaneously that this view 

 is incorrect, and that Asp. niger secretes an enzyme (tannase) that 

 is precipitable by alcohol, and is able of itself, in a sterilised 

 solution, to split up tannin (digallic acid) into gallic acid, a yield 

 of 98.7 per cent, of this acid being obtained from pure tannin. 

 In cultures the sparingly soluble gallic acid separates in fine 

 crystals from the tannin solution. This process has been patented 

 (Ger. Pat. 13,187, of 1901) for the production of gallic acid on a 

 commercial scale. The dextrose (12-15 per cent.) observed by 

 van Tieghem as accompanying gallic acid in the product from 

 commercial tannin is not a fission product from the glucoside, 

 but an impurity. Moreover, tannase is formed only in the case 

 of cultures on substrata containing tannin. Its optimum tem- 

 perature is about 67 C., and it splits up tannates as well as 

 phenyl- and methyl-salicylate. The same enzyme is probably 

 concerned in the formation of gallic acid in opium fermentation, 

 CALMETTE (II.) stating that Asp. niger plays the chief part in the 

 fission of tannin during that process, and also in the inversion of 

 the sugar into dextrose during this prolonged fermentation, which 

 occupies ten to twelve months. Both the dextrose and dextrin 

 are oxidised into calcium oxalate, without the alkaloids being 

 affected. Asp. niger is well known as a fungus preferring acid 

 substrata (solutions of organic acids), on which it thrives ; and 

 since it also occurs on gall-nuts and extracts of these, its spon- 

 taneous appearance in tannin- and opium-fermentation is 

 easily accounted for. It is certain that spontaneous green, 

 vegetative growths of Penicillium species, that need further 

 investigation, play a chief part in the fission of tannin. More- 

 over, the gallic acid fermentation of gall-nut tannin was ascribed 



