Catalyzes the removal of two reducing equivalents (oxidative decarboxylation) from the cysteine residue of the C-terminal meso-lanthionine of epidermin to form a --C==C-- double bond. Binds 1 FMN per subunit. Homododecamer. Belongs to the HFCD (homooligomeric flavin containing Cys decarboxylase) superfamily.