Conversion of glycerol 3-phosphate to dihydroxyacetone phosphate. Required for growth on glycerol and for glycerol metabolism. a quinone + sn-glycerol 3-phosphate = a quinol + dihydroxyacetone phosphate Up-regulated by glycerol and no inhibition by glucose. Polyol metabolism; glycerol degradation via glycerol kinase pathway; glycerone phosphate from sn-glycerol 3-phosphate (anaerobic route): step 1/1. Composed of a catalytic GlpA/B dimer and of membrane bound GlpC. Up-regulated by glycerol 3-phosphate. Unable to grow on glycerol. Can be complemented in trans by glpA2 under the control from a strong promoter. H.volcanii contains 2 glpABC operons, one located on the main chromosome and the other on megaplasmid pHV4. Belongs to the FAD-dependent glycerol-3-phosphate dehydrogenase family.