ABSTRACT
Microbial abatement of toluene using Aspergillus niger in coir packed upflow bioreactor was investigated in this study. Toluene degrading microbes were isolated from municipal sewage effluent and identified by 16s rRNA sequencing method. The microbes were cultured in 2% (v/v) toluene input per day, which exhibited 95% removal efficiency with the kinetic correction value (R2) of 0.9024 at the optimum flow rate of about 0.4m3h-1. Various parameters such as effect of flow rate, column height, elimination capacity and EBRT with removal efficiency for 50 day cycle were also optimized. The plug flow model for toluene degradation was properly expressed and the Monod kinetics constant Km and rmax values were determined as 2.25gm-3 and 67.773gm-3h-1 respectively for microbial growth rate.
Subject(s)
Air Pollutants/metabolism , Aspergillus niger/metabolism , Bioreactors , Toluene/metabolism , Air Pollution , Biodegradation, Environmental , Kinetics , Lignin/analogs & derivatives , Models, Theoretical , RNA, Ribosomal, 16S , Sewage/microbiology , Volatile Organic Compounds/metabolismABSTRACT
In the present study, a new biofiltration system involving a selective microbial strain isolated from aerated municipal sewage water attached with coir as packing material was developed for toluene degradation. The selected fungal isolate was identified as Trichoderma asperellum by 16S ribosomal RNA (16S rRNA) sequencing method, and pylogenetic tree was constructed using BLASTn search. Effect of various factors on growth and toluene degradation by newly isolated T. asperellum was studied in batch studies, and the optimum conditions were found to be pH 7.0, temperature 30 °C, and initial toluene concentration 1.5 (v/v)%. Continuous removal of gaseous toluene was monitored in upflow packed bed reactor (UFPBR) using T. asperellum. Effect of various parameters like column height, flow rate, and the inlet toluene concentration were studied to evaluate the performance of the biofilter. The maximum elimination capacity (257 g m(-3) h(-1)) was obtained with the packing height of 100 cm with the empty bed residence time of 5 min. Under these optimum conditions, the T. asperellum showed better toluene removal efficiency. Kinetic models have been developed for toluene degradation by T. asperellum using macrokinetic approach of the plug flow model incorporated with Monod model.
