Catalyzes the hydration of oleate at its cis-9-double bond to yield 10-hydroxyoctadecanoate. Cannot catalyze the reverse reaction. Is not active with saturated fatty acids and trans-, cis-5-, cis-6-, cis-8-, cis-11-, cis-13-, cis-14-, and cis-15-double bond unsaturated fatty acids as substrate; is only active on cis-9- and/or cis-12-double bond of unsaturated fatty acids without any trans-configurations, producing 10-hydroxy and 10,13-dihydroxy fatty acids. The hydration of unsaturated fatty acids is suggested to be a detoxification mechanism and a survival strategy for living in fatty acid-rich environments. (R)-10-hydroxyoctadecanoate = (9Z)-octadecenoate + H2O Binds 1 FAD per subunit. FAD does not seem to be involved in catalysis but rather in the structural stabilization of the enzyme. kcat is 470 min(-1) with oleate as substrate. The catalytic efficiency with oleate as substrate is 3.5-fold higher than that with palmitoleate, the second favored substrate. Optimum pH is 6.5 with oleate as substrate. Optimum temperature is 25 degrees Celsius with oleate as substrate. After 120 minutes, the enzyme activity is nearly unchanged at 25 degrees Celsius, but is reduced to only 25% at 35 degrees Celsius. Lipid metabolism; fatty acid metabolism. Homodimer. Belongs to the oleate hydratase family.