The enzymatic detoxification of the mycotoxin deoxynivalenol: identification of DepA from the DON epimerization pathway

Abstract

SummaryThe biological detoxification of mycotoxins, including deoxynivalenol (DON), represents a very promising approach to address the challenging problem of cereal grain contamination. The recent discovery of Devosia mutans 17‐2‐E‐8 (Devosia spp. 17‐2‐E‐8), a bacterial isolate capable of transforming DON to the non‐toxic stereoisomer 3‐epi‐deoxynivalenol, along with earlier reports of bacterial species capable of oxidizing DON to 3‐keto‐DON, has generated interest in the possible mechanism and enzyme(s) involved. An understanding of these details could pave the way for novel strategies to manage this widely present toxin. It was previously shown that DON epimerization proceeds through a two‐step biocatalysis. Significantly, this report describes the identification of the first enzymatic step in this pathway. The enzyme, a dehydrogenase responsible for the selective oxidation of DON at the C3 position, was shown to readily convert DON to 3‐keto‐DON, a less toxic intermediate in the DON epimerization pathway. Furthermore, this study provides insights into the PQQ dependence of the enzyme. This enzyme may be part of a feasible strategy for DON mitigation within the near future.

Detoxification of Mycotoxins through Biotransformation

“…A dehydrogenase responsible for the selective oxidation of deoxynivalenol (DON, 38) at C-3 position by converting DON (38) to 3-keto-DON (39) was revealed from the bacterium Devosia sp. ( Figure S16) [42].…”

“…Aflatoxin B 1 (AFB 1 , 1) Aflatoxicol (37) Fungi Aspergillus niger, Eurotium herbariorum, Rhizopus sp. [41] Deoxynivalenol (DON, 38) 3-Keto-DON (39) Devosia mutans (bacterium) [42] Fomannoxin (40) Fomannoxin alcohol (41) Pinus sylvestris cell cultures [44] Rhizosphere-associated bacterium Streptomyces sp. AcH 505 [48] Zearalenone(ZEN, 33) α-Zearalenol (42) Candida tropicalis (fungus) [45] Fungi: Saccharomyces cerevisae, Torulaspora delbruckii, Zygosaccharomyces rouxii, Pichia fermentans, and several yeast strains of the genera Candida, Hansenula, Brettanomyces, Schizosaccharornyces and Saccharomycopsis [46] Fungi Rhizopus sp.…”

Deoxynivalenol: Masked forms, fate during food processing, and potential biological remedies

“…(2016) observed that Devosia mutans 17‐2‐E‐8 from soil completely converted DON into the major metabolite 3‐keto‐DON and the secondary metabolite 3‐epi‐DON under aerobic conditions. Carere, Hassan, Lepp, and Zhou (2018) and Hassan et al. (2017) investigated the relevant enzymatic mechanism underlying epimerization.…”

“…He et al (2015) and He et al (2016) observed that Devosia mutans 17-2-E-8 from soil completely converted DON into the major metabolite 3-keto-DON and the secondary metabolite 3-epi-DON under aerobic conditions. Carere, Hassan, Lepp, and Zhou (2018) and Hassan et al (2017) investigated the relevant enzymatic mechanism underlying epimerization. Similarly, enrichment cultures from a maize field and a wastewater treatment plant, a microbial community with at least six bacterial genera, 13 aerobic bacteria from soil and wheat leaves belonging to the genera Nocardioides and Devosia, a microbial consortium called DX100 from soil, Devosia sp.…”

The Identification of DepB: An Enzyme Responsible for the Final Detoxification Step in the Deoxynivalenol Epimerization Pathway in Devosia mutans 17-2-E-8

“…17-2-E-8) has been shown to transform DON to 3- epi -DON through a two-step process ( He et al, 2016 ; Hassan et al, 2017 ). Recently, the first enzyme in D ON ep imerization (Dep) pathway, DepA, was identified as a pyrroloquinoline quinone (PQQ)-dependent dehydrogenase ( Carere et al, 2017 ). This enzyme readily converts DON to 3-keto-DON and can be expressed heterologously in E. coli.…”