Methyltransferase required for the conversion of 2-phytyl-1,4-beta-naphthoquinol to phylloquinol. demethylphylloquinol + S-adenosyl-L-methionine = H(+) + phylloquinol + S-adenosyl-L-homocysteine Cofactor biosynthesis; phylloquinone biosynthesis. Belongs to the class I-like SAM-binding methyltransferase superfamily. MenG/UbiE family.