FAD-dependent monooxygenase; part of the gene cluster that mediates the biosynthesis of pyranoviolin A, a pyranonigrin analog with a C-3 methoxy group (PubMed:33117309). Initially, the PKS portion of pyvA synthesizes C-10 carbon chain from 5 molecules of malonyl-CoA, which is then condensed with the thiolation (T) domain-bound glycine activated by the adenylation (A) domain (PubMed:33117309). The subsequent chain release by Dieckmann condensation (DKC) could be catalyzed by the TE domain present at the C-terminus of pyvA and/or the alpha/beta hydrolase pyvD, installing the tetramic acid moiety (Probable). The FAD-dependent monooxygenase pyvC next epoxidizes one of the olefins of the polyketide part, and the epoxide ring-opening induces the dihydro-gamma-pyrone ring formation (Probable). The cytochrome P450 monooxygeanse pyvB would be responsible for the 2 consecutive reactions, in which the dihydro-gamma-pyrone is oxidized to gamma-pyrone and C-7 is hydroxylated to yield pyranonigrin F (Probable). Finally, the O-methyltransferase pyvH methylates the C-3 hydroxy group to complete the biosynthesis (Probable). Secondary metabolite biosynthesis. Belongs to the paxM FAD-dependent monooxygenase family.