NADH PRODUCTION FROM NAD+ WITH A FORMATE DEHYDROGENASE SYSTEM INVOLVING IMMOBILIZED CELLS OF A METHYLOTROPHIC ARTHROBACTER STRAIN

A convenient and economical method of NADH production from NAD+ has been established using a formate dehydrogenase system involving immobilized cells of a methanol-utilizing bacterium, Arthrobacter sp, KM62. Four kinds of cell entrapment were studied. An immobilized cell preparation showing a high NADH production activity was obtained by entrapment in a κ-carrageenan gel lattice. The NADH-producing activity of the immobilized cells was investigated under various conditions. The NADH-producing activity was evoked on the addition of Triton X-100 to the reaction mixture. The conditions for the continuous production of NADH with an immobilized cell column were also investigated. When a reaction mixture containing 10 μmol (6.63 mg) ml-1 NAD+ was passed through the column (1.2 × 20 cm) containing 1.62 g (as dry weight) of immobilized cells, at a space velocity of 0.125 at 35°C, complete conversion was attained. © 1990.