Catalyzes the conversion of L-ornithine to N(5)-hydroxyornithine, the first step in the biosynthesis of all hydroxamate-containing siderophores, such as the secreted triacetylfusarinine C (TAFC) involved in iron uptake and the intracellular iron storage compound desferriferricrocin (DFFC). L-ornithine + NADPH + O2 = H2O + N(5)-hydroxy-L-ornithine + NADP(+) L-ornithine + NADH + O2 = H2O + N(5)-hydroxy-L-ornithine + NAD(+) Binds 1 FAD per subunit. Siderophore biosynthesis. Homotetramer. Essential for viabiliy. Grows only on siderophore-supplemented growth-medium, but shows decreased conidiation. Belongs to the lysine N(6)-hydroxylase/L-ornithine N(5)-oxygenase family.