Acontinuous fixed-bed bioreactor for MTBE biodegradation by enhanced alginate-calcium immobilized beads of methylibium petroleiphilum PM1

Methyl tert-butyl ether(MTBE)biodegradation was investigated using a fixed-bed bioreactor with enhanced immobilized gel beads of Methylibium petroleiphilum PM1 under aerobic conditions.Various techniques were explored to improve the mechanical sytength Of immobilized gel beads.Batch experiments showed the optimized conditions were:the Ca2+ concentration in the crosslinking solution and in the growth medium were 3％and 0.002 M.Respectively;the polyethyleneimine concentration used was 0.002％.During the biodegradation process.The number of viable cells increased from 8.0 × 108 cells mL-1 的1.7×109 cells mL-1.Implying that the structure of the immobilized carrier could be preferable for cell growth.A fixed-bed bioreactor with enhanced immobihzed gel beads as media was used to treat M11BE wastewater.The results showed that the removal efficiency increased with dissolved oxygen (DO) and hydraulic residence time (HRT).The fixed-bed bioreactor could be maintained stably for 50 d.The concentrations of MTBE in the influent and efnuent were nearly 10mg/L and less than 0.3 mg/L,respectively.The fingerprint Of PCR-DGGE confirmed the dominance of PM 1 in the immobilized gel beads.These results suggested that the enhanced immobilized gel beads of PM 1 in bioreactor might be apphcable for treatment of MTBE—contaminated groundwater.