Removal of gaseous n-valeric acid in the air by Rhodococcus sp. B261 immobilized onto ceramic beads

n-Valeric acid, one of the main malodorous pollutants from livestock houses was eliminated with a biofilter prepared with Rhodococcus sp. B261 immobilized onto ceramic beads. The strain was isolated from composted pig faeces and grown in an artificial medium containing volatile fatty acids as a carbon source. The cells were immobilized onto ceramic beads in vacuo. The beads were aseptically incubated at 37 °C, pH 8.0, for 24 h for activation of the cells. The beads with immobilized cells (3.36 x 10⁹ c.f.u./g ceramic beads) and moisture content of 35% (w/w) were packed into a glass column equipped with a water jacket to keep the temperature constant. One hundredseventy ppm of gaseous n-valeric acid were removed for 11 days at 30 h^-1 (space velocity) and 37 °C.