Biochemical Effects of Fatty Acid and its Derivatives on L-Glutamic Acid Fermentation

Abstract

1. For the growth of Brev. lactofermentum, oleic acid was completely replaced for biotin; trace amount of biotin was not required. This result applied to the case of many lactic acid bacteria except L. arabinosus. 2. Oleic acid had a growth-inhibitory effect as well as the stimulatory one. This dualistic property was based on the concentration of the acid in the culture medium and was ob-served generally with unsaturated fatty acids irrespective of their chemical structures, com-prising the position and the number of double bond and cis- and trans-form. 3. The growth inhibition caused by higher concentration of oleic acid was changed into the growth stimulation in the three different ways: (a) the prolongation of culture, (b) the esterification of oleic acid, and (c) the addi-tion of the hydrophilic ester of saturated fatty acid as a detoxicant. 4. When added into a medium containing oleic acid, Tween 60 had not only the de-toxificating effect but also synergetic effect; the oleic acid-sparing effect in the presence of small amount of oleic acid and the lag period. reducing effect. 5. The results obtained with Brev. lacta-fermentum confirmed other investigators' ob-servations on the properties of oleic acid and on the relation between saturated and un-saturated fatty acid for lactic acid bacteria.