Air-contd. vinyl acetate (I) was biodecompd. in a culture of polypropylene ring packing - immobilized Pseudomonas fluorescens strain at 35 degrees C and pH 7 in a cocurrent tricle bed reactor. A conversion of I was 60-95% depending on the liq.-gas stream flow (1.3-3.2 m(3)/h) at the initial I concn. (up to 380 ppm) and time. The growth rate of the microorganism was correlated to the initial I concn.