Improving hexane removal by enhancing fungal development in a microbial consortium biofilter

Area of Science:

• Environmental Biotechnology
• Bioremediation
• Microbial Ecology

Background:

• Biofilter efficiency for hydrophobic pollutants is limited by gas-liquid mass transfer.
• Fungal inoculation is proposed to improve pollutant removal in biofilters.
• Hexane vapor uptake was investigated to assess fungal contribution to removal efficiency.

Purpose of the Study:

• To evaluate the impact of fungi on hexane vapor removal efficiency in biofilters.
• To compare the performance of neutral and acid-conditioned biofilters inoculated with mixed microbial cultures.
• To identify and assess the hexane removal potential of specific fungal strains.

Main Methods:

• Perlite-packed biofilters (2.6 L) inoculated with bacteria and fungi were operated under neutral and acid conditions.
• Hexane vapor inlet loads were varied to determine elimination capacities (EC).
• Bacterial inhibitors were used to assess fungal contribution; fungal isolates were identified and tested in small biofilters.

Main Results:

• Acidic biofilters achieved higher hexane elimination capacities (100-150 g.m-3.h-1) compared to neutral systems (60 g.m-3.h-1).
• Bacterial inhibitors did not significantly affect EC in acid systems, indicating fungal dominance.
• Isolated fungi (Cladosporium and Fusarium spp.) showed significant hexane EC (40-50 g.m-3.h-1) in short-term experiments.

Conclusions:

• Fungal presence, particularly under acidic conditions, significantly enhances hydrophobic pollutant removal in biofilters.
• Hydrophobic aerial hyphae of fungi facilitate faster absorption of hydrophobic compounds compared to bacterial biofilms.
• Cladosporium and Fusarium spp. demonstrate potential for effective hexane biofiltration.