-An intracellular esterase from Propionibacterium freudenreichii ssp. freudenreichii ITG 14 was purified by anion exchange and gel filtration chromatography. The enzyme had a molecular weight of 47 400 g . mol -1 as determined by gel filtration chromatography, with an optimum activity on α-naphthyl-acetate at pH 6.0 and at 65 °C, with K M = 1.2 mmol . L -1 . The esterase hydrolyzed synthetic substrates of low molecular weight (C2-C4), and among triglycerides only triacetin. Sulfhydryl group reagents and metal chelators had limited or no effect on enzyme activity; highest inhibition was observed with phenylmethylsulfonylfluoride (PMSF). Propionibacterium freudenreichii