Expression, characterization and application of the deoxynivalenol dehydrogenase from Devosia yakushimensis.

Abstract

Background: Deoxynivalenol (DON) is one of the type-B trichothecene mycotoxins generally produced by Fusarium fungi and widely pollutes wheat and other grains, causing a great loss in grain yield and significant threat to human health. Enzymatic treatment of DON has displayed a significant role in controlling its levels in recent years.

Results: Here, the DON dehydrogenase from Devosia yakushimensis (DeDDH) is reported. DeDDH exhibited the highest activity in an environment of 35 °C and pH 7.5. In addition, the residual activity of DeDDH was about 40% after pre-incubation at 80 °C for 0.5 h, suggesting a good thermostability. The presence of Ca²⁺ significantly boosted the activity of DeDDH, but substituting Ca²⁺ with other ions could hardly retain the activity. At the optimal conditions, DeDDH efficiently degraded 75% DON (45 μg mL^-1) within 4 h. Notably, when three cofactors, PQQ, PMS and DCPIP, were added together, more than 90% DON (45 μg mL^-1) was quickly degraded in the first 40 min.

Conclusion: The residues Thr485 and Leu521 were found to be significant to the activity of DeDDH by site-directed mutagenesis, much different from other DON dehydrogenases. Nevertheless, further research on the crystal structure determination of DeDDH, key catalytic residue identification, catalytic activity and thermostability modification still needs to be conducted for application in industry. © 2024 Society of Chemical Industry.