Fungal co-culture improves the biodegradation of hydrophobic VOCs gas mixtures in conventional biofilters and biotrickling filters.

The present study systematically evaluated the potential of Candida subhashii, Fusarium solani and their consortium for the abatement of n-hexane, trichloroethylene (TCE), toluene and α-pinene in biofilters (BFs) and biotrickling filters (BTFs). Three 3.2 L BFs packed with polyurethane foam and operated at a gas residence time of 77 s with an air mixture of hydrophobic volatile organic compounds (VOCs) were inoculated with C. subhashii, F. solani and a combination of thereof. The systems were also operated under a BTF configuration with a liquid recirculating rate of 2.5 L h-1. Steady state elimination capacities (ECs) of total VOCs of 17.4 ± 0.7 g m-3 h-1 for C. subhashii, 21.2 ± 0.8 g m-3 h-1 for F. solani and 24.4 ± 1.4 g m-3 h-1 for their consortium were recorded in BFs, which increased up to 27.2 ± 1.6 g m-3 h-1, 29.2 ± 1.9 g m-3 h-1, 37.7 ± 3.3 g m-3 h-1 in BTFs. BTFs supported a superior biodegradation performance compared to BF, regardless of the VOCs. Moreover, a more effective VOC biodegradation was observed when C. subhashii and F. solani were grown as a consortium. The microbial analysis conducted revealed that the fungi initially introduced in each BF represented the dominant species by the end of the experiment, with C. subhashii gradually overcoming F. solani in the system inoculated with the fungal consortium.