Efficient Degradation of Aflatoxin B<sub>1</sub> and Zearalenone by Laccase-like Multicopper Oxidase from <i>Streptomyces thermocarboxydus</i> in the Presence of Mediators
Multicopper oxidases (MCOs) are a diverse group of enzymes that could catalyze the oxidation of different xenobiotic compounds, with simultaneous reduction in oxygen to water. Aside from laccase, one member of the MCO superfamily has shown great potential in the biodegradation of mycotoxins; however...
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| Autores principales: | , , , , , , , , , , |
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| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
MDPI AG
2021
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| Materias: | |
| Acceso en línea: | https://doaj.org/article/dc663b3e70b845a191f2615f349f25de |
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| Sumario: | Multicopper oxidases (MCOs) are a diverse group of enzymes that could catalyze the oxidation of different xenobiotic compounds, with simultaneous reduction in oxygen to water. Aside from laccase, one member of the MCO superfamily has shown great potential in the biodegradation of mycotoxins; however, the mycotoxin degradation ability of other MCOs is uncertain. In this study, a novel MCO-encoding gene, <i>StMCO</i>, from <i>Streptomyces thermocarboxydus,</i> was identified, cloned, and heterologously expressed in <i>Escherichia coli</i>. The purified recombinant <i>St</i>MCO exhibited the characteristic blue color and bivalent copper ion-dependent enzyme activity. It was capable of oxidizing the model substrate ABTS, phenolic compound DMP, and azo dye RB5. Notably, <i>St</i>MCO could directly degrade aflatoxin B<sub>1</sub> (AFB<sub>1</sub>) and zearalenone (ZEN) in the absence of mediators. Meanwhile, the presence of various lignin unit-derived natural mediators or ABTS could significantly accelerate the degradation of AFB<sub>1</sub> and ZEN by <i>St</i>MCO. Furthermore, the biological toxicities of their corresponding degradation products, AFQ<sub>1</sub> and 13-OH-ZEN-quinone, were remarkably decreased. Our findings suggested that efficient degradation of mycotoxins with mediators might be a common feature of the MCOs superfamily. In summary, the unique properties of MCOs make them good candidates for degrading multiple major mycotoxins in contaminated feed and food. |
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