Purification and characterization of an extracellular esterase from Arthrobacter nicotianae 9458

A 32 kgmol -1 extracellular esterase from Arthrobacter nicotianae 9458 was purified to homogeneity by 4 chromatographic steps. The optimum pH and temperature for enzyme activity for -naphthyl butyrate were 7.0 and 30 C, respectively. The esterase retained between 50-55% of the maximum activity at pH 5.5 and 15 C and was completely inactivated by heating for 1 min at 65 C. Among the -naphthyl derivatives of various chain length (C2-C18:1), the highest activity was on -naphthyl butyrate. The enzyme was moderately active on tributyrin and was less active on tricaproin. The esterase was markedly inhibited by phenylmethylsulfonyl fluoride and to a lesser extent by EDTA. Divalent cations such as Fe 2+ , Sn 2+ , Ca 2+ and Hg 2+ also inhibited the enzyme. This characterization showed that the extracellular esterase of Arthrobacter nicotianae 9458 may contribute to the ripening of smear surface-ripened cheeses.