LS3J<At<Y 

 NEW V..ÏÎK 

 ftOTANICAL 



Researches on the formation of diastase 

 by Aspergillus niger van Tieghem 



by 



G. L. Funke. 

 I. CRITICAL SUMMARY OF LITERATURE. 



Many investigators hâve already considered the question, whether 

 bactena and fungi are able to modify the sécrétion of their enzymes 

 quahtativel y and (or) quantitatively under the influence of nutri- 

 tion. Most of them hâve how^ever arranged their experiments m a 

 very primitive way, in that they vvere not careful to exclude ail 

 possible disturbing influences, and almost ail of them tackled the 

 subject from a différent angle. It does not therefore, surprise us in 

 the least that very contradictory results hâve been obtained. 



Even the first investigators of this question are unable to agrée, 

 whether the organisms only form their enzymes m the case of 

 necessity i. e. whether the sécrétion is influenced qualitatively by 

 nutrition. Wortmann e. g. stated in 1882 that bactena only 

 secrète amylase when cultivated on starch. As he however worked 

 with a mixture of putrefying bactena, even he himself could not 

 name the matenal, used for his experiments. 



Biisgen however mentions in 1885 that Aspergillus Oryzae 

 produces amylase even when glucose is the only available source 

 of Carbon. 



Fermi 1890 — 1891 cultivated bacteria on proteids and on sugars, 



and found that in the case of proteids only proteolytic enzymes are 



<^^ formed.In 1895however hefound with Mont es ano that. 4s/)g;'g///î*5 



' niger secrètes invertase, when glycérine is given as the only source 



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