Conversion of glycerol 3-phosphate to dihydroxyacetone. Uses fumarate or nitrate as electron acceptor (By similarity). a quinone + sn-glycerol 3-phosphate = a quinol + dihydroxyacetone phosphate 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. Loosely bound to the cytoplasmic membrane often occurring in vesicles associated with fumarate reductase. Belongs to the FAD-dependent glycerol-3-phosphate dehydrogenase family.