Catalyzes oxidative C-C coupling reaction to polymerize flaviolin and form highly conjugated pigments which protect the soil bacterium from deleterious effects of UV irradiation (three isomers of biflaviolin and one triflaviolin). 2 flaviolin + H(+) + O2 + 2 reduced [2Fe-2S]-[ferredoxin] = 3,3'-biflaviolin + 2 H2O + 2 oxidized [2Fe-2S]-[ferredoxin] 2 flaviolin + H(+) + O2 + 2 reduced [2Fe-2S]-[ferredoxin] = 3,8'-biflaviolin + 2 H2O + 2 oxidized [2Fe-2S]-[ferredoxin] kcat is 1.4 min(-1) with flaviolin as substrate (at pH 7.5 and 37 degrees Celsius). kcat is 0.02 min(-1) with 2-hydroxy-1,4-naphthoquinone as substrate (at pH 7.5 and 25 degrees Celsius). Pigment biosynthesis. The structural studies suggest catalysis likely occurs through proton relay via a 'proton wire' formed by water molecules in the active site. Belongs to the cytochrome P450 family.