208 



H. G. WOOD, F. W. LEAVER 



VOL. 12 (1953) 



The propionic acid bacteria ferment 3, 4, 5, and 6 carbon polyalcohols and therefore 

 present an unique opportunity to compare the fermentation of compounds of different 

 length. Our present knowledge of the fermentation is based almost entirely on results 

 from either 3 or 6 carbon substrates. It was considered possible that the fermentations 

 of 4 and 5 carbon substrates might involve production or utilization of CO 2 to form 

 3 or 6 carbon compounds which then might be fermented by the usual mechanisms. 

 If so, such a mechanism might be revealed either by an increased CO 2 turnover and 

 increased fixation of CO 2 or fixation into positions other than the carboxyl groups. This 

 possibility has been investigated in the present study. This work and other investigations 

 have been discussed recently by Leaver and Wood^^. 



PRODUCTS FROM 3, 4, 5, AND 6 CARBON SUBSTRATES 



The products of the fermentation of 3 to 6 carbon substrates are shown in Tables I, 

 II, and III. The fermentations shown in Tables I and II are taken from experiments which 



TABLE I 



THE FERMENTATION OF 3, 4, 5 AND 6 CARBON SUBSTRATES BY PROLIFERATING CELLS OF 



P. pentosaceum, 49W 



* Calculated from reducing value after hydrolysis, on the basis of a 6 carbon sugar with a reducing 

 value equivalent to glucose*^. 



250 ml of medium containing 2.0 per cent, substrate, 1.75 per cent, sodium bicarbonate and 

 0.4 per cent, yeast extract in 300 ml flask; N, gas. Incubated 25daysat 30° C. Procedures and methods, 

 Wood and Werkman^*. 



TABLE II 

 fermentation of 3, 4, 5 AND 6 carbon substrates by washed cells of p. pentosaceum, 49W 



2 per cent, substrate, 1.75 per cent, sodium bicarbonate and 2.7 per cent, wet cells; 150 ml in 

 300 ml flask under Nj. Temperature 30° C, time 10 days. Procedures and methods as in Wood and 

 Werkman^*. The fermentations were set up under sterile conditions with bacteria from 6 days growth 

 on glycerol i.o per cent., yeast extract 0.4 per cent., and K-phosphate buffer o.i M , pH 7.2. 



References p. 221I222. 



