Efficient decontamination of zearalenone, the mycotoxin of cereal pathogen, by transgenic yeasts through the expression of a synthetic lactonohydrolase gene.
Zearalenone (ZEN), an estrogenic mycotoxin produced by several Fusarium species, is converted to a non-estrogenic product by a detoxifying enzyme of Clonostachys rosea. Previously, we investigated whether recombinant Saccharomyces cerevisiae carrying this detoxification gene, zhd101, can remove 2 microg ml(-1) of ZEN in a liquid culture. Although the transgenic yeasts eliminated most of the ZEN, they also converted a significant amount to a poor substrate, beta-zearalenol, which remained in the medium. In this study, we synthesized a codon-optimized zhd101 gene and investigated whether the transgenic yeast strain can overcome the problem of insufficient detoxification of ZEN. Importantly, within 48 h of incubation at 28 degrees C or 8 h of incubation at 37 degrees C, the transgenic yeasts completely eliminated 2 microg ml(-1) of ZEN in the medium without accumulating even a trace amount of beta-zearalenol. The result suggests that incomplete ZEN detoxification attributed to the action of an endogenous yeast beta-reductase can be overcome by simply increasing the expression of the detoxifying gene.
Takahashi-Ando
Naoko
N
Laboratory for Remediation Research, Plant Science Center, RIKEN, 1-7-22 Suehiro, Tsurumi, Yokohama, Kanagawa, 230-0045, Japan.
Tokai
Takeshi
T
Hamamoto
Hiroshi
H
Yamaguchi
Isamu
I
Kimura
Makoto
M
D000595:Amino Acid Sequence; D001673:Biodegradation, Environmental; D003666:Decontamination / Q000379:methods; D008969:Molecular Sequence Data; D010957:Plasmids; D015202:Protein Engineering; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000494:pharmacology; D012441:Saccharomyces cerevisiae / Q000254:growth & development / Q000378:metabolism*; D016415:Sequence Alignment; D015025:Zearalenone / Q000037:antagonists & inhibitors*; D015029:Zeranol / Q000031:analogs & derivatives / Q000378:metabolism
D011994:Recombinant Proteins; C029659:zearalenol; D015025:Zearalenone; D015029:Zeranol