82 FERMENTATION BY MUCORS. 



coveries were afterwards supplemented by other workers who 

 will be mentioned later on. 



The degree of susceptibility towards alcohol is an important 

 factor in solving the question as to the suitability of these fungi 

 for the purposes of the distiller, since it is this sensitivity which, 

 other conditions being equal, determines the attainable produc- 

 tion of alcohol. Another iniiuential factor is the fermentative 

 activity, i.e. the duration of time in which a given quantity of 

 alcohol is produced. A few reports on this point are collected 

 below : — 



Mucor muredo has produced :— 



According to 



After 



In 



Pasteur (III) 

 Brepeld (XV.) 

 FiTZ (XI.) at 30° C. 

 Hansen (VIII.) at 23° C. 

 and at room temperature 



14 months | wort 



7 weeks 

 15 days 

 6 months 



must 

 wort 

 wort 



Alcohol 



1.8 % bv weight 

 2.6% ■ „ 

 0.8 % „ 

 0.5 % by volume 



3-0 % . 



Mnror racemosus has produced 



According to 



FiTZ (IX.) . 



Brefeld (XIII.) 

 Brefeld(XIII.) 



Pasteur (III.) . 



Pasteur (III) • 



FiTz (XI.) . 



After 



f " many \ 

 \ months " J 



2 years 



2^ years 

 1^ monthfi 



In 



At 



Hansen (VIII.) . > 12 months 



must 



f nutrient) 

 \ soln. J 



wort 



must 

 w'ort 



25-26° C 



15° C. 



f high I 

 \temiJ.J 

 f room \ 

 \temp.J 



25-30° C. 

 / room\ 

 \temp. j 



Alcohol 



3.5-4.0% b weight 

 4-5% 



up to 



5-5% 

 3.3% 



3-4% 

 2.3-2.7% 



7.0% by volume 



According to U. Gayon (V.) the production of alcohol by 

 Mncor sidno-^us ceases as soon as the amount formed attains 1.5 

 to 2.0 per cent. ; but Hansen, on the other hand, succeedecl m de- 

 tecting 5.4 per cent, by volume in wort cultures at 22 O., atter 

 61 months. Jhimv drcineVoides, according to Gayon (VI.), pro- 

 duces 5.5 per cent, of alcohol. Mucor eredus, according to Hansen, 

 when grown in wort cultures at room temperature, furnishes 8 

 per cent by volume in ih months, but only 7 per cent, at 25 G. 

 It therefore probably forms an exception to the rule applying to 

 all the other MtmorecB mentioned, namely, that they produce 

 larger quantities of alcohol at higher temperatures than at lower. 

 Thus, according to Fixz (IX.), Mucur racenwsus is very sluggish 



