Biodegradation of 2,5-dimethylpyrazine in gas and liquid phase by the fungus Fusarium solani

BACKGROUND
Alkylpyrazines are odorous compounds conferring pleasant aromas to baked and roasted foods. However, they are also emitted during food processing, creating a nuisance for the operators and the community. Only a few bacterial isolates have been shown to degrade 2,5-methylpyrazine (DMP), as a model alkylpyrazine. This work aimed to study the ability of DMP biodegradation by the filamentous fungus Fusarium solani.

RESULTS
Evidence of the degradation of DMP was collected in axenic cultures of F. solani in liquid mineral medium and over a saturated solid support using DMP as the sole carbon and energy source. DMP was used for growth as evidenced by the formation of an abundant aerial mycelium over a solid support, accompanied by the production of 70 ppm CO2 mg−1 dry biomass, and by its consumption in liquid media at a rate of 58.3 mg g−1 biomass h−1, a value comparable to those reported for bacteria. A non-axenic biofilter was mounted, fed with a DMP-laden air stream, and operated for 40 days. The maximum DMP elimination capacity achieved was 8.5 g m−3 h−1 at an inlet load of 11.3 g m−3 h−1 (an 80% relative efficiency).

CONCLUSION
Fusarium solani uses DMP as a carbon source, showing great potential for its abatement in a biofilter. High-throughput DNA sequencing of biofilter samples showed that it was the most representative member of the community, with a relative abundance surpassing 97%, indicating that it played a pivotal role in the biofilter. © 2021 Society of Chemical Industry (SCI).