Botany. — "The injluence of hydrogen ion concentratio7i upon the 

 action of the amylase of Asperyillus niger". Bj G. L. Funke. 

 (Communicated by Prof. P. A. F. C. Went). 



(Communicated at the meeting of January 28, 1922). 



Aspergillus niger produces large quantities of amylase, part of 

 which migrates into its nutiitive surrounding. In the mean lime the 

 fungus forms acids which cause that medium to have a high hydrogen 

 ion concentration. As this however seemed not to influence un- 

 favourably the action of the amylase, the supposition was justified 

 that the amylase of Aspeigillus niger could not have its optimal 

 action at the same hydrogen ion concentration as the ptyaline which 

 works best at a nearly neutral or faintly acid reaction (4 and 5). 



Therefore I made a preliminary investigation in the way as 

 has been indicated first by Sörensen (1). Buffer solutions however 

 were made according to the methods of Clark and Lubs (7). 



Generally the same amounts of enzyme solution out of the 

 nutritive liquid were mixed up with buffer solution and amylum 



1 Ph 



solution 0.16 •/«• The hydrogen ion concentration of this mixture 

 was determined by aid of colorimetric indicators, the i-ate of 

 hydrolysis of the amylum by the iodine reaction. 



