Effects of short chain fatty acids on the production of heat-labile enterotoxin from enterotoxigenic Escherichia coli.

Each addition of some short chain fatty acids (SCFAs) into casamino acids-yeast extract culture media at a concentration of 2 mg/ml reduced the production of heat-labile enterotoxin (LT) from enterotoxigenic Escherichia coli in proportion to the elongation of carbon chain from C-2 to C-7. The LT-production was inversely recovered by the addition of longer chain fatty acids. The reduction of LT-production by SCFAs seems to depend on the disturbance of the biosynthesis of LT itself, since LT was not detected in the cells treated with n-heptyric acid at 2 mg/ml, which abolished the LT-production.