134 LABORATORY MANUAL OF MICROBIOLOGY 



When the filter paper shows evidences of disintegration, make 

 transfers to new tubes of Omeliansky's medium (enrichment 

 cultures). 



Exercise 65 



Number of Aerobic Cellulose-decomposing Bacteria in Soil^ 



Prepare a series of medium-sized test tubes containing 5 cubic 

 centimeters of Medium 85 (the CaCOa may be left out and a 

 trace of FeS04 introduced) and a strip of 

 paper. Part of the paper should protrude 

 above the surface of medium. 



Prepare a series of soil dilutions (1 : 10, 

 1:100, 1:1,000) and inoculate 1 cubic 

 centimeter of each dilution into one tube 

 of medium. 



Take out, with a sterile pipette, 1 cubic 

 centimeter from the tube inoculated with 

 cytlphaga^'^'^luUnTol 1 ' l^O^O dilution and add to a fresh tube of 

 and Clayton.) sterile medium, to give a dilution of 



1:5,000. 

 If further dilutions are desired the last step is repeated. 

 The tubes are incubated at 25 to 30°C. and examined daily. 

 Presence of cellulose-decomposing bacteria will be shown by the 

 decomposition of the paper just at the surface of the liquid. 

 Examine bacteria by Nigrosin method. 



Exercise 56 

 Themophilic Fermentation of Cellulose 



Prepare four long tubes (about 25 centimeters each) with 

 20 cubic centimeters each of the Cellulose peptone medium 

 (Medium 89). 



Treat as follows: 



(a) Control — not inoculated. 



(6) About 1 gram of fresh horse manure. 



(c) About 1 gram of well-rotted leaf mold. 



(d) About 1 cubic centimeter of a culture of Clostridium ther- 

 mocellum. 



1 DuBos, R. J., J. BacL, 15 : 223, 1928. 



