Distribution of glycerol dehydrogenase and glycerol kinase activity in halophilic archaea

A constitutive NAD⁺-dependent glycerol dehydrogenase activity was detected in Halobacterium salinarium and Halobacterium cutirubrum. Optimal activity was found at 3 M KCl and pH 8-10. No glycerol dehydrogenase activity could be demonstrated in representatives of the genera Haloferax and Haloarcula, even when grown in the presence of glycerol, or in Halobacterium saccharovorum and Halobacterium sodomense. Glycerol kinase activity was shown to be present constitutively in all halophilic archaea examined. The finding that glycerol dehydrogenase is found only in part of the halophilic arachaea makes dihydroxyacetone an improbable candidate as the precursor for the glycerol moiety of halobacterial lipids.