Isolation of a Highly Efficient Sulfamethoxazole-degrading Bacteria and Its Degradation Properties
With respect to antibiotic-contaminated sites, sulfamethoxazole (SMX) is considered at the highest risk level and a substance for priority control. In order to deepen the application of microbial remediation for the degradation of SMX, SMX-degrading bacteria were enriched and fortified from contaminated samples through co-metabolism. Strain 2-T was isolated and identified as Pseduochrobactrum sp. In terms of the SMX degradation, this strain was highly efficient when compared to the other isolated strains, exhibiting degradation efficiency up to 92%. Results show that the optimal degradation conditions of strain 2-T are at 25°C and pH 7.0, with a 10% bacterial inoculum and a low initial SMX concentration. Under the optimal conditions, the initial SMX concentration was within 1-30 mg/L and the degradation process conformed to first-order kinetics. The SMX concentration was affected by the bacterial biomass and degradation time. Furthermore, SMX degradation was in accordance with the Monod equation. The activation energy of the SMX degradation reaction by strain 2-T at different temperatures was lower than 44.89 kJ/mol. This study provides a basis for use of the SMX-degrading strain 2-T for bioremediation of SMX-contaminated wastewater.