title: Biotransformation of the mycotoxin zearalenone by fungi of the genera Rhizopus and Aspergillus.
abstract: Zearalenone (ZEN) is a nonsteroidal estrogenic mycotoxin biosynthesized by various Fusarium fungi. These fungal species frequently infest grains; therefore, ZEN represents a common contaminant in cereal products. The biotransformation of ZEN differs significantly from species to species, and several metabolites are known to be formed by animals, plants, and microorganisms. The aim of the present study was to investigate the microbial conversion of ZEN by species of the genera Rhizopus and Aspergillus representing relevant fungi for food processing (e.g. fermentation). To monitor the ZEN metabolism, ZEN was added to liquid cultures of the different fungal species. After a period of 3 days, the media were analyzed by HPLC-MS/MS for metabolite formation. Two Aspergillus oryzae strains and all seven Rhizopus species were able to convert ZEN into various metabolites, including ZEN-14-sulfate as well as ZEN-O-14- and ZEN-O-16-glucoside. Microbial transformation of ZEN into the significantly more estrogenic α-zearalenol (α-ZEL) was also observed. Additionally, a novel fungal metabolite, α-ZEL-sulfate, was detected. Semi-quantification of the main metabolites indicates that more than 50% of initial ZEN may be modified. The results show that fungal strains have the potential to convert ZEN into various metabolites leading to a masking of the toxin, for example in fermented food.
authors.affiliation: Department of Analytical Chemistry, Reference Materials, BAM Federal Institute for Materials Research and Testing, Berlin, Germany; Department of Materials and Environment, BAM Federal Institute for Materials Research and Testing, Berlin, Germany.
authors.forename: Antje
authors.initials: A
authors.lastname: Brodehl
authors.forename: Anne
authors.initials: A
authors.lastname: Möller
authors.forename: Hans-Jörg
authors.initials: HJ
authors.lastname: Kunte
authors.forename: Matthias
authors.initials: M
authors.lastname: Koch
authors.forename: Ronald
authors.initials: R
authors.lastname: Maul
mesh_terms: D001236:Aspergillus oryzae / Q000254:growth & development / Q000378:metabolism*; D001711:Biotransformation; D005516:Food Microbiology; D005670:Fusarium / Q000378:metabolism; D008658:Inactivation, Metabolic; D009183:Mycotoxins / Q000378:metabolism*; D012233:Rhizopus / Q000254:growth & development / Q000378:metabolism*; D015025:Zearalenone / Q000378:metabolism*
chemical_list: D009183:Mycotoxins; D015025:Zearalenone
keywords: conjugation; fermentation; metabolites; microbial conversion; α-zearalenol