Purification and characterization of an extracellular esterase from Arthrobacter nicotianae 9458

Overview & Synopsis

A 32 kg$\cdot$mol$^{-1}$ extracellular esterase from Arthrobacter nicotianae 9458 was purified to homogeneity by 4 chromatographic steps. The optimum pH and temperature for enzyme activity for $\beta$-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 $\beta$-naphthyl derivatives of various chain length (C2-C18:1), the highest activity was on $\beta$-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.