Catalyzes the hydration of oleate at its cis-9-double bond to yield 10-hydroxyoctadecanoate, and of linoleate at its cis-9- and cis-12-double bond to yield 10-hydroxy-12-octadecenoate and 10,13-dihydroxyoctadecanoate. Is not active on trans-double bonds and esterified fatty acids as substrate; is only active on cis-9- and/or cis-12-double bond of C16 and C18 fatty acids without any trans-configurations, producing 10-hydroxy and 10,13-dihydroxy derivatives. Appears to play a role in oleic acid detoxification and bacterial virulence. (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 67 min(-1) and 101 min(-1) with oleate and linoleate as substrate, respectively. Lipid metabolism; fatty acid metabolism. Monomer and homodimer. Both forms seem to be active. In strain lacking this gene, consumption of the free fatty acids from the medium is reduced to about 50% of that of the wild-type. The mutant strain also appears to be 2-fold more sensitive to oleic acid than wild-type, whereas no changes in sensitivity to linoleic acid is observed. The mutant shows increased survival in blood with reduced adherence and internalization to human keratinocytes. Unsaturated fatty acids are toxic for many bacteria due to deteriorating effect on bacterial cellular membrane and disruption of bacterial fatty acid synthesis. The hydration of unsaturated fatty acids is suggested to be a detoxification mechanism and a survival strategy for living in fatty acid-rich environments (PubMed:20145247). Belongs to the oleate hydratase family. Extended N-terminus.