Purification and characterization of an extracellular esterase from Arthrobacter nicotianae 9458

A 32 kg.mol(-1) extracellular esterase from Arthrobacter nicotianae 9458 wa s purified to homogeneity by 4 chromatographic steps. The optimum pH and te mperature for enzyme activity for beta-naphthyl butyrate were 7.0 and 30 de grees C, respectively. The esterase retained between 50-55% of the maximum activity at pH 5.5 and 15 degrees C and was completely inactivated by heati ng for 1 min at 65 degrees C. Among the beta-naphthyl derivatives of variou s chain length (C2-C18:1), the highest activity was on beta-naphthyl butyra te. The enzyme was moderately active on tributyrin and was less active on t ricaproin. The esterase was markedly inhibited by phenylmethylsulfonyl fluo ride and to a lesser extent by EDTA. Divalent cations such as Fe2+, Sn2+, C a2+ and Hg2+ also inhibited the enzyme. This characterization showed that t he extracellular esterase of Arthrobacter nicotianae 9458 may contribute to the ripening of smear surface-ripened cheeses.