MIXED-FUNCTION OXIDASE-INHIBITORS AFFECT PRODUCTION OF THE OFF-FLAVOR MICROBIAL METABOLITE GEOSMIN

Geosmin (1,10-trans-dimethyl-trans-(9)-decalol) is produced by the filamentous bacteria Streptomyces tendae Ettlinger and imparts an intense muddy "off-flavor" which degrades the quality of drinking water and pond-raised fish. The effects of the cytochrome P450 mixed-function oxidase inhibitors piperonyl butoxide [α-[2-(2-butoxyethyoxy)ethoxy]-4,5-(methylenedioxy)-2-propyltoluene], and MGK-264 [N-octyl bicycloheptene dicarboximide] on dry matter, pigment, and geosmin production were determined in S. tendae. Neither piperonyl butoxide nor MGK-264 affected dry matter production, but both compounds decreased pigment synthesis compared to untreated controls. Exposure to MGK-264 and piperonyl butoxide produced differing effects on geosmin production. Piperonyl butoxide (300 μM) induced approximately a 400% increase in geosmin levels, while MGK-264 (300 μM) reduced geosmin levels approximately 40% compared to untreated controls. © 1990.