A fixed-film bioscrubber of Microbacterium esteraromaticum SBS1-7 for toluene/styrene biodegradation

Abstract

In the present study, a fixed-film bioscrubber (FFBS) of BTEX-degrading bacterium Microbacterium esteraromaticum SBS1–7 with ‘AQUAPOROUSGEL® or APG’ supporting material was continuously fed with toluene- or styrene-contaminated gas stream for 172 days. Response Surface Methodology (RSM) was used to optimize the biofilm formation on APG as well as the toluene biodegradation in mineral salt medium (MM). The results suggested that 1000 ppm of yeast extract (YE) was necessary for biofilm formation of SBS1–7. The optimized combination of YE and toluene concentration exhibiting the highest biofilm formation and toluene removal was further employed in an up-scale FFBS operation. The maximum Elimination Capacity (ECmax) of 203 g·m−3·h−1 was obtained at the toluene Inlet Loading Rate (ILR) of 295 g·m−3·h−1. FFBS of SBS1–7 was able to withstand a 5-day shutdown and required only 24 h to recover. Moreover, when the inlet Volatile Organic Compound was shifted to styrene, FFBS required only 24 h for adaptation and the system was able to efficiently remove ~95% of styrene after that. Finally, the performance of the bioscrubber when operated in 2 different modes of operation (FFBS vs Biotricking Filter or BTF) were compared. This study evidently demonstrated the robustness and stability of FFBS with M. esteraromaticum SBS1–7.