"Is involved in the reduction of 2,3-digeranylgeranylglycerophospholipids (unsaturated archaeols) into 2,3-diphytanylglycerophospholipids (saturated archaeols) in the biosynthesis of archaeal membrane lipids. Catalyzes the formation of archaetidic acid (2,3-di-O-phytanyl-sn-glyceryl phosphate) from 2,3-di-O-geranylgeranylglyceryl phosphate (DGGGP) via the hydrogenation of each double bond of the isoprenoid chains. Is also probably able to reduce double bonds of geranyl groups in CDP-2,3-bis-O-(geranylgeranyl)-sn-glycerol and archaetidylserine, thus acting at various stages in the biosynthesis of archaeal membrane lipids."xsd:string