CarbonSource-Dependent Inhibition ofxylOperonExpression ofthePseudomonas putida TOLPlasmid

Abstract

TOLplasmid-encoded degradation ofbenzyl alcohol byPseudomonas putida isinhibited byglucose andother compounds related tothemaincarbohydrate metabolism inPseudomonas species. We report herethatthiseffect isexerted atthelevel ofexpression ofthexylcatabolic operons,andtwoxylpromoters, PuandPs, wereidentified astheprimary targets ofthis inhibition. xylpromoter activation was alsoinhibited byglucose intheheterologous Escherichia coilsystem, apparently nothowever bytheclassical mechanism ofenteric catabolite repression. Microbial degradation ofaromatic compounds isan importantapproach toeliminating toxic pollutants fromtheenvironment (2,23,25).Therespective catabolic pathways have generally beenanalyzed underconditions inwhichthetarget compound ispresent asthesole growth-supporting substrate.