ACTIVITY OF TOLUENE-DEGRADING PSEUDOMONAS-PUTIDA IN THE EARLY GROWTH-PHASE OF A BIOFILM FOR WASTE-GAS TREATMENT

A biological trickling filter for treatment of toluene-containing wast e gas was studied. The overall kinetics of the biofilm growth was foll owed in the early growth phase. A rapid initial colonization took plac e during the first three days. The biofilm thickness increased exponen tially, whereas the increase of active biomass and polymers was linear . In order to investigate the toluene degradation, various toluene deg raders from the multispecies biofilm were isolated, and a Pseudomonas putida was chosen as a representative of the toluene-degrading populat ion. A specific rRNA oligonucleotide probe was used to follow the tolu ene-degrading P. putida in the multispecies biofilm in the filter by m eans of number and cellular rRNA content. P. putida appeared to detach from the biofilm during the first three days of growth, after which P . putida was found at a constant level of 10% of the active biomass in the biofilm. Based on the rRNA content, the in situ activity was esti mated to be reduced to 20% of cells grown at maximum conditions in bat ch culture. The toluene degraded by P. putida was estimated to be a mi nor part (11%) of the overall toluene degradation. (C) 1997 John Wiley & Sons, Inc.