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Medientyp:
E-Artikel
Titel:
Azoreductase activity of dye-decolorizing bacteria isolated from the human gut microbiota
Beteiligte:
Zahran, Sara A.;
Ali-Tammam, Marwa;
Hashem, Abdelgawad M.;
Aziz, Ramy K.;
Ali, Amal E.
Erschienen:
Springer Science and Business Media LLC, 2019
Erschienen in:
Scientific Reports, 9 (2019) 1
Sprache:
Englisch
DOI:
10.1038/s41598-019-41894-8
ISSN:
2045-2322
Entstehung:
Anmerkungen:
Beschreibung:
<jats:title>Abstract</jats:title><jats:p>The gut microbiota enriches the human gene pool and contributes to xenobiotic metabolism. Microbial azoreductases modulate the reduction of azo-bonds, activating produgs and azo polymer-coated dosage forms, or degrading food additives. Here, we aimed to screen the healthy human gut microbiota for food colorant-reducing activity and to characterize factors modulating it. Four representative isolates from screened fecal samples were identified as <jats:italic>E. coli</jats:italic> (AZO-Ec), <jats:italic>E. faecalis</jats:italic> (AZO-Ef), <jats:italic>E. avium</jats:italic> (AZO-Ev) and <jats:italic>B. cereus</jats:italic> (AZO-Bc). Both AZO-Ef and AZO-Ev decolorized amaranth aerobically and microaerophilically while AZO-Ec and AZO-Bc had higher aerobic reduction rates. The isolates varied in their activities against different dyes, and the azo-reduction activity mostly followed zero-order reaction kinetics, with a few exceptions. Additionally, the isolates had different pH dependence, e.g., AZO-Ec was not affected by pH variation while AZO-Bc exhibited variable degradation kinetics at different pH levels. Cell-free extracts showed NADH-dependent enzymatic activities 14–19 times higher than extracellular fractions. FMN did not affect the reducing activity of AZO-Ef cell-free extract, whereas AZO-Ec, AZO-Ev and AZO-Bc had significantly higher reduction rates in its presence (<jats:italic>P</jats:italic> values<jats:italic> = </jats:italic>0.02, 0.0001 and 0.02, respectively). Using Degenerate primers allowed the amplification of azoreductase genes, whose sequences were 98–99% similar to genes encoding FMN-dependent-NADH azoreductases.</jats:p>