The effect of agitation on the rate of acid formation by Lactobacillus delbrueckii Abstracted from a thesis submitted by R. E. West in partial fulfilment of the requirements for the degree of Doctor of Philosophy in the University of Michigan, 1957. Presented before the Fermentation Subdivision of the Division of Agricultural and Food Chemistry, at the 134th National Meeting of the American Chemical Society, Chicago, Illinois, September 10, 1958.

Abstract

The effect of agitation on the rate of acid formation by the microaerophilic organism Lactobacillus delbrueckii was studied. Fermentations were conducted at constant temperature and pH, and with the continuous addition of a nutrilite source. The range of agitator speeds was from 85 to 720 rev/min. The acid formation rate was found to increase with increasing agitator speeds and decrease with decreasing speeds if corn-steep liquor was the nutrilite source. No effect of agitation was observed with yeast extract as the nutrilite source. The data from corn-steep liquor media were found to be consistent with a mass transfer mechanism, but did not warrant a conclusion as to the specific nature of the effect of agitation. It was concluded, however, that the effect of agitation on the acid formation rate was at most very small.