Screening Of High Efficient Degradation Strains Of Sulfonamides And Their Degradation Characteristics

Sulfonamides?SAS?are widely found in water,soil,animals and plants,especially in urban sewage.They are toxic and difficult to degrade.They are often detected in the effluent of the secondary sedimentation tank of the sewage treatment plant.Exogenous bacteria strengthen the sewage biological treatment unit,which may reduce the discharge of antibiotics.In addition,the microbiological method is mild in treatment,has no secondary pollution,has low cost,and has a broad practical application prospect.On the basis of five strains which can survive in harsh environments and have excellent degradation effects,this paper intends to study the characteristics of five strains to degrade sulfanilamide antibiotics,in order to obtain the excellent bacteria or flora to deal with sulfanilamide antibiotics,and to develop various practical significance.By means of modern analytical methods such as ultraviolet spectrum,liquid chromatography,TOC analyzer,sulfamethoxazole and sulfamethylpyrimidine were selected as test pollutants,excellent degradation strains were screened and degradation characteristics were studied.The following results were achieved.?1?The study confirmed that NT16,FF and NG16 strains had the potential to efficiently degrade sulfonamide antibiotics.The three strains were able to grow in 10mg/L sulfamethoxazole and sulfamethylpyrimidine respectively.Among them,FF bacteria had a high removal efficiency for sulfamethoxazole,while NT16 bacteria had a strong removal ability for sulfamethylpyrimidine.?2?The highest OD_600nm00nm value of FF bacteria cells in an inorganic salt culture solution containing 10mg/L sulfamethoxazole was about 1.6,and its degradation ability is strong,and the degradation rate was about 22.4%at 240h.However,the growth and degradation of NG16 bacteria were inhibited to a certain extent by sulfamethoxazole,and even the cell death of NG16 bacteria was observed in the later stage;while the degradation rate of sulfamethoxazole at 240h was only 13.8%.?3?The mix of NT16 bacteria and FF bacteria had a stronger anti-sulfamethoxazole toxicity.The best mix of NT16 bacteria and FF bacteria is 2:3,and the mixed cells could grow rapidly in the medium containing 10mg/L sulfamethoxazole inorganic salt,the OD_600nm00nm value was more than 1.1 at 24h,and the degradation rate of sulfamethoxazole at 72h was more than 12%,which was far higher than that of single bacteria.?4?NT16 bacteria could grow rapidly in the sulfamethylpyrimidine inorganic salt culture solution,the OD_600nm00nm value was about 1.5 at 24 hours,and could be maintained above 1.0,and its degradation ability is strong,and the degradation rate was about28.6%at 240h.However,NG16 bacteria was inhibited by sulfamethylpyrimidine,and the degradation of sulfamethylpyrimidine was not observed in the early stage,and its degradation rate at 240 h was only 10.7%.?5?For sulfamethylpyrimidine,the complex bacteria of NT16 bacteria and FF bacteria had better degradation effect.The optimal ratio of NT16 bacteria:FF bacteria is 3:2.The mixed bacteria of this ratio could grow fastest in the medium containing10mg/L sulfamethylpyrimidine inorganic salt,and its OD_600nm00nm value was more than 1.2at 24h,and its degradation efficiency is much higher the situation of single bacteria,especially in the initial 96h of degradation.