Abstract

Different kinetic models have been proposed to describe the elimination of hydrophobic volatile organic compounds (VOCs) by fungal biofiltration. In this process the ratio of the initial substrate concentration (C-b0(p)) to the initial biomass (X-0) has been shown to influence the cell yield. This paper presents a study of the effect of the C-b0(p)/X-0 ratio on observed cell yield (Y-obs) in a fixed bed batch system (microcosm) using a gaseous carbon source, as an approximation to its application in the fungal biofiltration of hydrophobic VOCs. Essays were carried out in fixed-bed microcosms using the filamentous fungus Fusarium solani as a biological agent and n-pentane as a carbon and energy source. The results indicated that Y-obs in the gas phase is inversely proportional to the C-b0(p)/X-0 ratio, with values of 0.9 to 0.35 g(biomass) g(pentane)(-1) being obtained when the C-b0(P)/x(0) ratio is changed from 0.1 to 1.0 g(pentane) g(biomass)(-1).The results indicate that more than 60% of n-pentane was consumed due to energy spilling, and that strong dissociation of catabolism from anabolism occurred at higher C-b0(p)/X-0 ratios.