Abstract
Herein we report the use of Pseudomonas putida F1 biofilms grown
on carbonized cellulosic fibers to achieve biodegradation of airborne
VOCs in the absence of any bulk aqueous phase media. It is believed that
direct exposure of gaseous VOC substrates to biomass may eliminate
aqueous phase mass transfer resistance and facilitate VOC capture and
degradation. When tested with toluene vapor as a model VOC, the
supported biofilm could grow optimally at 300 ppm toluene and 80%
relative humidity, with a specific growth rate of 0.425 day
-1. During long-term VOC biodegradation tests in a
tubular packed bed reactor, biofilms achieved a toluene degradation rate
of 2.5 mg g DCW -1 h
-1 during the initial exponential growth phase.
Interestingly, the P. putida F1 film kept biodegrading activity
even at the subsequent stationary non-growth phase. The supported
biofilms with a biomass loading of 20% (wt) could degrade toluene at a
rate of 1.9 mg g DCW -1 h
-1 during the stationary phase, releasing CO
2 at a rate of 6.4 mg g DCW
-1 h -1 at the same time (indicating
100% conversion of substrate carbon to CO 2). All the
specific degradation rates are much higher than what can be gleaned from
previously reported work. It also demonstrates the feasibility of
biofilm growth and direct gas phase degradation of VOCs without
requiring any bulk aqueous phase.