HEW Ym^m. 



pOTANICAJt 



THE MANNITOL-PRODUCING ORGANISMS IN SILAGE 



G. P. PLAISANCE and B. W. HAMMER 



From the Bacteriology and Dairy Sections of the Iowa Agricultural Experiment 



Station 



Received for publication December 27, 1920 

 INTRODUCTION 



The chemistry section of the Iowa agricultural experiment 

 station has shown (Dox and Plaisance, 1917 a and b) that manni- 

 tol is a normal constituent of silage and has reported experiments 

 indicating that '4t is formed in silage fermentation by bacterial 

 reduction of the fructose-half of the sucrose molecule." In 

 silage, the mannitol is produced in considerable amounts, simul- 

 taneously with the acids, the carbon dioxide and the alcohol 

 and "its presence accounts in large measure for the deficit noted 

 when the sum of these products is balanced with the fermented 

 sugar." 



The results reported in the present paper^ deal with the isola- 

 tion from silage of organisms capable of producing mannitol 

 when grown in pure cultures in corn, corn juice, and various 

 other materials. 



HISTORICAL 



The presence of mannitol in the higher plants, in both the 

 higher and lower fungi, and in various fermented materials 

 such as wine, vinegar and sauerkraut, as well as its production 

 by organisms, has already been dealt with in some little detail 

 in the publications of the Iowa station. It is evident that 

 mannitol fermentation has long been known and that it is more 

 or less common. 



'■ The work herein dealt with was carried out in 1917 and was to have been 

 reported at the meeting of the American Society of Bacteriologists in that year. 

 The National Research Council, however, requested that the report be delayed 

 because of the possible use of mannitol in the manufacture of explosives. 



431 



JOURNAL OF BACTERIOLOGT, VOL. VI, NO. 5 



