Operational aspects of SO2 removal and microbial population in an integrated-bioreactor with two bioreaction zones

Abstract

An integrated-bioreactor, which consisted of a suspended zone and an immobilized zone, was applied to treat gases containing SO 2 . The removal of SO 2 in suspended zone differed slightly from that in immobilized zone. The influences of operational aspects such as SO 2 load, temperature, and pH on integrated-bioreactor performance and bacterial community composition were investigated. The synergistic action of the two zones led to effective reduction of SO 2 , and the total removal efficiencies with the inlet concentration of 91-117 mg/m 3 , were over 85 % in steady state. Paenibacillus sp. and Lysinibacillus sp. dominated both zones as desulfurization bacteria. Results of polymerase chain reaction-denaturing gradient gel electrophoresis followed by clone library analysis indicated that temporal shifts in bacterial community composition in both zones developed differently. Differences in the concentration of introduced SO 2 and supported mode of microorganisms for survival, confirmed that bacterial community composition and abundance significantly differed among individual zones.