Rhinocladiella similis biodegraded volatile organic compounds (VOCs) of different polarity in gas-phase biofilters. Elimination capacities, (EC) of 74 g(hexane) m(-3) h(-1), 230 g(ethanol) m(-3) h(-1), 85 g(toluene) m(-3) h(-1) and 30 g(phenol) m(-3) h(-1) were obtained. EC values correlated with the solubility of the VOCs. R. similis grown with n-hexane or ethanol in biofilters packed with Perlite showed that the surface hydrophobicity was higher with n-hexane than ethanol. The hydrophobin-like proteins extracted from the mycelium produced with n-hexane (15 kDa) were different from those in the ethanol biofilter (8.5 kDa and 7 kDa).