Biodegradation of typical pharmaceutical compounds by a novel strain Acinetobacter sp.

摘要

A novel sulfamethoxazole (SMX)-degrading strain,Acinetobactersp., was used to degrade other pharmaceutical compounds, including sulfadiazine (SD), sulfamethazine (SMT), trimethoprim (THM), triclosan (TCS), diclofenac (DFC) and carbamazepine (CBZ). The experimental results showed thatAcinetobactersp. can completely degrade SMX, SD and SMT, but with different mineralization efficiency.Acinetobactersp. can mineralize 98.8% of SMX, while only 17.5% and 20.5% for SD and SMT, respectively. The intermediate products of SMX, SD and SMT degradation were tentatively identified. Based on the intermediates, it is inferred that the initial step for degrading sulfonamides byAcinetobactersp. was the amidation of the amino groups in the benzene ring. The presence of methyl in the heterocyclic ring could induce the formation of methylase. By comparing the intermediates of SMX, SD and SMT degradation, it is concluded thatAcinetobactersp. preferred attacking the oxazole ring. However,Acinetobactersp. cannot degrade THM, TCS, DFC and CBZ, whileAcinetobactersp. can still degrade SMX in the respective presence of THM, DFC and CBZ, although the degradation rate decreased. Moreover, the presence of TCS could completely inhibit the degradation of SMX byAcinetobactersp.