4. Conclusion
P. putida F1 was successfully preloaded onto CCFs and applied for
airborne toluene degradation. Studies showed that the P. putidaF1 was able to grow on the CCF support and eventually formed mature
biofilms under feeding with gaseous toluene. The CCF-supported P.
putida F1 biofilms can grow at the RH range from 40 to 80% and the
biomass grow faster at higher humidity levels. The optimal specific
growth rate of P. putida F1 in gas phase was actually comparable
to that in liquid phase. The CCF-supported P. putida F1 enable
both growth-associated and non-growth associated biodegradation
activities. Operated without any bulk liquid medium phase, the biofilm
achieved direct degradation of gas phase VOC at rates of about one-order
of magnitude higher than what has been previously reported for liquid
culturing or immobilized cells. These results suggest that liquid phase
mass transfer is a significant limiting factor for traditional
biodegradation reactions, and biofilms operated in gas phases can
promote efficient substrate-cell interactions and thus intensifying
biotransformation reactions.