Catalyzes the hydrolysis of esters (PubMed:15808744). Displays esterase activity toward pNP-butyrate (PubMed:15808744). May stimulate mixed-acid fermentation by acting as a fermentation/respiration switch that down-regulates respiration and up-regulates fermentation rates (PubMed:15169777). a carboxylic ester + H2O = a carboxylate + an alcohol + H(+) Forms a 1:1 complex specifically with the unphosphorylated form of the EIIA component of the glucose-specific PTS system (IIAGlc). Deletion of the gene increases cell respiration rate on several sugars including glucose. Increased expression results in an increased fermentation rate on sugars with the concomitant accumulation of mixed-acid fermentation products. Belongs to the FrsA family.