( 1202 ) 
Influence of acid and alkali on lipase. 
The great influence of acids on the decomposition of fat by lipase 
produced by microbes, is most evident when the microbes which 
form acid from glucose, such as Penicillium glaucum, Oidium lactis, 
B. lipolyticum a, B. Stutzeri, or B. fluorescens liquefaciens, are 
cultivated on brothagar with 5°/, glucose, solidified on a thin 
layer of fat in a culture box, or in a fatted tube of broth with 
5°/, glucose. These microbes do not split fat in the medium by 
diffusing lipase; the fat remains quite unaltered. It is true that it 
is slightly attacked through direct contact, for example by the mycelium 
of moulds, when this has grown through the agar and subsequently 
touches the fat, or by bacteria in the tubes when in a layer near 
the surface they locally also touch it. The decomposition of the fat 
does not, however, take place deeper in the tube and it is always 
excluded when there is some distance between the fat and the 
organism. 
In the accompanying figures A and B may be observed the 
influence of acid formation and of the presence of acid in a medium 
on the action of microbic lipase. 
A represents a culture box with broth-gelatin solidified on a 
layer of fat. 
B is similar to A but contains broth-gelatin to which 5°/, glucose 
has been added. 
On both media streaks are made only of fat-splitting bacteria, in 
the way as indicated in Fig. 1. 
In A all the bacteria make fields of splitted fat, as is distinctly 
to be seen; this is not the case in B where B. Stutzeri and B. 
8. Stutzer: 
B. lipoltyicum 4 
Ut 
ge" 
=S 
ES 
SS 
2 
= 
‘'~ 
S 
Ss 
B. lipolyticum « 
Fig. 1. 
