Influence of casein hydrolyzates and amino acids on glucose ferementation by Propionibacterium freudenreichii.

Although the pathways by which propionibacteria ferment glucose have not been completely established, it has been noted by several investigators that relatively large numbers of bacterial cells are required for reasonable reaction rates. During studies on glucose fermentationi by intact cells of Propionibacterium freudenreichii we have found that the addition of the medium components described by Delwiche (1950) resulted in marked stimulation of the rate of glucose utilization. The present paper reports an investigation of this phenomenon with the finding that the stimulatory materials reside in the nitrogenous components of the medium.