An l-glucitol oxidizing dehydrogenase from Bradyrhizobium japonicum USDA 110 for production of d-sorbose with enzymatic or electrochemical cofactor regeneration
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A gene in Bradyrhizobium japonicum USDA 110, annotated as a ribitol dehydrogenase (RDH), had 87 % sequence identity (97 % positives) to the N-terminal 31 amino acids of an l-glucitol dehydrogenase from Stenotrophomonas maltophilia DSMZ 14322. The 729-bp long RDH gene coded for a protein consisting of 242 amino acids with a molecular mass of 26.1 kDa. The heterologously expressed protein not only exhibited the main enantio selective activity with d-glucitol oxidation to d-fructose but also converted l-glucitol to d-sorbose with enzymatic cofactor regeneration and a yield of 90 %. The temperature stability and the apparent K m value for l-glucitol oxidation let the enzyme appear as a promising subject for further improvement by enzyme evolution. We propose to rename the enzyme from the annotated RDH gene (locus tag bll6662) from B. japonicum USDA as a d-sorbitol dehydrogenase (EC 18.104.22.168).
KeywordsDehydrogenase Cofactor regeneration Electrochemistry l-glucitol d-sorbose
Financial support from the European Community through the FP7-NMP-2007-SMALL 1 collaborative project ERUDESP is gratefully acknowledged. We thank Dr. Josef Zapp, Saarland University, for the NMR and IR determinations, and Birgit Hasper for the technical assistance.
- Kaneko T, Nakamura Y, Sato S, Minamisawa K, Uchiumi T, Sasamoto S, Watanabe A, Idesawa K, Iriguchi M, Kawashima K, Kohara M, Matsumoto M, Shimpo S, Tsuruoka H, Wada T, Yamada M, Tabata S (2002) Complete genomic sequence of nitrogen-fixing symbiotic bacterium Bradyrhizobium japonicum USDA110. DNA Res 9:189–197PubMedCrossRefGoogle Scholar
- Kornberger P, Giffhorn F, Kohring GW (2010) Dehydrogenases, electrochemical co-factor regeneration. In: Flickinger MC (ed) Encyclopedia of industrial biotechnology, bioprocess, bioseparation, and cell technology. Wiley, Hoboken, pp 1888–1898Google Scholar