US EPA

4072237 

Journal Article 

Characterization of membrane-bound dehydrogenases of Gluconobacter oxydans 621H using a new system for their functional expression 

Mientus, M; Kostner, D; Peters, B; Liebl, W; Ehrenreich, A 

2017 

Yes 

Applied Microbiology and Biotechnology
ISSN: 0175-7598
EISSN: 1432-0614 

101 

8 

3189-3200 

English 

28064365 

10.1007/s00253-016-8069-4 

Acetic acid bacteria are used in biotechnology due to their ability to incompletely oxidize a great variety of carbohydrates, alcohols, and related compounds in a regio- and stereo-selective manner. These reactions are catalyzed by membrane-bound dehydrogenases (mDHs), often with a broad substrate spectrum. In this study, the promoters of six mDHs of Gluconobacter oxydans 621H were characterized. The constitutive promoter of the alcohol dehydrogenase and the glucose-repressed promoter of the inositol dehydrogenase were used to construct a shuttle vector system for the fully functional expression of mDHs in the multi-deletion strain G. oxydans BP.9 that lacks its mDHs. This system was used to express each mDH of G. oxydans 621H, in order to individually characterize the substrates, they oxidize. From 55 tested compounds, the alcohol dehydrogenase oxidized 30 substrates and the polyol dehydrogenase 25. The substrate spectrum of alcohol dehydrogenase overlapped largely with the aldehyde dehydrogenase and partially with polyol dehydrogenase. Thus, we were able to resolve the overlapping substrate spectra of the main mDHs of G. oxydans 621H. The described approach could also be used for the expression and detailed characterization of substrates used by mDHs from other acetic acid bacteria or a metagenome.