Micro-organisms of Maple Sap t99 



Fermentation tubes of nutrient broth containing -''< of 

 mannit showed gas production in 24 hours at 25 ° C. but not at 

 20 . At the end of two days 10% of gas had developed at 20 

 while at 30 25% had formed. Cultures six days old shown 1 

 a development of about 40% of gas, approximately one-half of 

 which was absorbed by sodium hydroxid. Evidences of fermen- 

 tation of maltose at 20 were pronounced in 15 hours, progress- 

 ing rapidly till 40 to 50% of gas was formed, which was similar 

 in composition to that produced upon other sugars. No gas was 

 produced upon glycerin broth. 



Fermentation of potato starch. — Potato fermentation tubes 

 were prepared by placing cylinders of potato in the closed arm 

 and filling with distilled water. The tubes were sterilized by 

 steaming on each of three consecutive days, and inoculated with 

 a 2 mm. loop from young broth cultures. Gas production oc- 

 curred within 15 hours after inoculation in tubes held at 30 . 

 At the end of three days tubes kept at 20 showed 25 to 35 per- 

 cent of the closed arm filled with gas. The gas w r as tested with 

 sodium hydroxid and the flame test and found to contain carbon 

 dioxid and hydrogen. 



Potato extract was prepared by boiling potatoes one-half 

 hour in distilled water and decanting the liquid upon a filter. 

 Fermentation tubes of the medium developed good growth. Gas 

 consisting of carbon dioxid and hydrogen was produced by the 

 second day. Tests for reducing sugars and for aldehydes made 

 on the third day negative results. These ingredients were sought 

 by the Fehling solution and ammoniacal silver nitrate methods, 

 respectively. Potato extract to which 4% of sucrose was added, 

 developed a remarkable growth. The fluid became milky and 

 slightly stringy and developed a yeasty odor very much like that 

 produced in sap. 



Gas production in modified Uschinsky solution containing 

 carbohydrates. — To modified Uschinsky solution 2% of the fol- 

 lowing carbohydrates were added, maltose, dextrose, sucrose, 

 lactose and mannit. The media were placed in fermentation 



