Mannitol oxidation in two Micromonospora isolates and in representative species of other actinomycetes

Abstract

Mannitol kinase and mannitol 1 phosphate dehydrogenase activities were detected in 2 Micromonospora isolates. The presence of these enzyme activities indicates that mannitol is catabolized first to mannitol 1 phosphate and then to fructose 6 phosphate. Mannitol oxidizing enzymes were also surveyed in representative species of 4 other genera of actinomycetes. Mannitol 1 phosphate dehydrogenase was detected in cell free extracts of Streptomyces lactamdurans. In contrast, cell free extracts of Mycobacterium smegmatis, Nocardia erythrophila, Streptomyces lavendulae, and Actinoplanes missouriensis contained mannitol dehydrogenase activity but no detectable mannitol 1 phosphate dehydrogenase activity. The mannitol dehydrogenase activities in the latter species support the operation of a pathway for catabolism of mannitol that involves the oxidation of mannitol to fructose, followed by phosphorylation to fructose 6 phosphate.