A HIGHLY REGIOSELECTIVE ESTERASE FROM PENICILLIUM-FREQUENTANS IMI-92265

An esterase isolated from Penicillium frequentans IMI 92265 selectivel y hydrolyses the acetoxyethyl ester in preference to the acetoxymethyl esters in the triacetate substrate 1,4-diacetoxy-2-acetoxymethylbutan e (1) which was converted to 4-acetoxy-3-acetoxymethylbutan-1-ol (2) i n good yield. The enzyme gave no detectable hydrolysis of 1,3-diacetox y-2-acetoxymethylpropane (4). When immobilised to a cyanogen bromide a ctivated Sepharose resin the enzyme was highly stable and showed no lo ss of regioselectivity in the hydrolysis of (1). A method is described for the elective isolation of microorganisms which have the ability t o hydrolyse (1).