title: Characterization of thermostable FMN-dependent NADH azoreductase from the moderate thermophile Geobacillus stearothermophilus.
abstract: The gene encoding an FMN-dependent NADH azoreductase, AzrG, from thermophilic Geobacillus stearothermophilus was cloned and functionally expressed in recombinant Escherichia coli. Purified recombinant AzrG is a homodimer of 23 kDa and bore FMN as a flavin cofactor. The optimal temperature of AzrG was 85 degrees C for the degradation of Methyl Red (MR). AzrG remained active for 1 h at 65 degrees C and for 1 month at 30 degrees C, demonstrating both superior thermostability and long-term stability of the enzyme. AzrG efficiently decolorized MR, Ethyl Red at 30 degrees C. Furthermore, the enzyme exhibited a wide-range of degrading activity towards several tenacious azo dyes, such as Acid Red 88, Orange I, and Congo Red. These results suggested the sustainable utilization of G. stearothermophilus as an azo-degrading strain for AzrG carrying whole-cell wastewater treatments for azo pollutants under high temperature conditions.
authors.affiliation: Division of Biotechnology and Macromolecular Chemistry, Graduate School of Engineering, Hokkaido University, N13-W8, Kita-ku, Sapporo, 060-8628, Japan.
authors.forename: Ken'ichiro
authors.initials: K
authors.lastname: Matsumoto
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Mukai
authors.forename: Daiki
authors.initials: D
authors.lastname: Ogata
authors.forename: Fumi
authors.initials: F
authors.lastname: Shozui
authors.forename: John Masani
authors.initials: JM
authors.lastname: Nduko
authors.forename: Seiichi
authors.initials: S
authors.lastname: Taguchi
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Ooi
mesh_terms: D001391:Azo Compounds / Q000378:metabolism; D002942:Circular Dichroism; D003001:Cloning, Molecular; D003067:Coenzymes / Q000378:metabolism; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics; D005486:Flavin Mononucleotide / Q000378:metabolism; D001411:Geobacillus stearothermophilus / Q000201:enzymology* / Q000235:genetics; D009243:NAD / Q000378:metabolism; D009247:NADH, NADPH Oxidoreductases / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D009601:Nitroreductases; D013379:Substrate Specificity
chemical_list: D001391:Azo Compounds; D003067:Coenzymes; D009243:NAD; D005486:Flavin Mononucleotide; D009247:NADH, NADPH Oxidoreductases; D009601:Nitroreductases; C021106:azoreductase