Enhanced Degradation of Sulfamethoxazole Using Immobilized Biomass Reactor

Abstract

Sulfamethoxazole (SMX) is a common antibiotic frequently detected in the environment. This study investigated enhanced substrate degradation using an immobilized biomass reactor. The degradation rates increased in the batch reactor operation, owing to the increased biomass of immobilized microorganisms in polyurethane foam (PUF). The degradation rate at 50 mg/L was 38.8±3.8 mg SMX/day, and immobilized microorganisms achieved 406.6±42.2 mg dry biomass/g dry PUF under optimum conditions. Two SMX-degrading bacterial strains, <i>Acinetobacter</i> sp. S1 and <i>Pseudomonas</i> sp. S2, were isolated from the immobilized biomass. Furthermore, this study analyzed the possible SMX degradation pathway based on the intermediates of each isolate. The cooperation of these isolated strains resulted in increased degradation and reduced produced metabolites. The degradation by the immobilized cells of the mixed isolated bacteria in continuous operation exceeded 93% SMX at the hydraulic retention time of 36 h at 50 mg/L.