The Acclimation And Degradation Characteristic Of Sulfamethoxazole Anaerobic Degraing Bacteria

As a common antibiotic,Sulfamethoxazole?SMX?is frequently detected in the real environment,resulting in persistent and persistent toxicological effects in the environment.To explore the anaerobic degradation of sulfamethoxazole degradation rule,selection of temperature and electron acceptor in anaerobic transformation is relatively important environmental factor,the investigation under the condition of the role of anaerobic activated sludge on the conversion efficiency and mechanism of SMX,therefore,this study enriched the anaerobic degradation of flora,the effects of the variety of temperature and different electron acceptor and concentration of electron acceptor SMX degradation efficiency and the effect of parsing the different redox conditions SMX anaerobic degradation mechanism and the relationship between microbial community structure,so as to provide theoretical basis for SMX anaerobic biological transformation.After 240 days of enrichment and domestication,the degradation rate of SMX was basically stable at about 40%.Test the utilization of TEA when anaerobic degradation enters a stable period.Under the conditions of different concentrations of SMX,both nitrate and SMX show a synergistic downward trend,and the concentration of SO₄^2-shows a trend of first decreasing and then increasing.From the analysis of different electron receptor concentrations,it can be seen that the electron receptor concentration affects the anaerobic degradation efficiency of SMX.When NO₃^-is TEA,the optimal TEA concentration is 1 mM.When SO₄^2-is TEA,the optimal TEA concentration ranges from 0.2 mM to 5 mM.When Fe?III?is used as TEA,the optimal TEA concentration ranges from 1 mM to 7 mM.Temperature affects the anaerobic biodegradation efficiency of SMX,and low temperature inhibits the anaerobic transformation of SMX.When SO₄^2-and Fe?III?are used as TEA,the anaerobic degradation of SMX has a better removal effect and the optimal temperature is 40^oC to 50^oC.When NO₃^-and MIX are used as TEA,the anaerobic degradation of SMX is relatively poor and the optimal temperature is 30^oC to 40^oC.The experimental comparison of biodegradation group A,adsorption group B and control group C showed that SO₄^2-and NO₃^-were used as TEA,and the removal of SMX in aqueous phase mainly depended on the redox effect of microorganisms.At different temperatures,the ions in the degradation system were analyzed,and the concentration of terminal electron acceptor ions decreased in the process of degradation under the single TEA condition,nitrite accumulated,and the degradation of SMX was inhibited under the mixed TEA condition.Degradation effect of TEA on SMX:>ferric sulfate>mixed with>nitrate.Under the condition of different terminal electron acceptor,intermediate degradation is detected in liquid as follows:4-amino-N-?5-hydroxy methyl-3-amino benzene sulfonamide,4-amino-N-?3-different oxazole-5-methyl?benzene sulfonamide?,4-amino-N-?3-oxazole-5-methyl?benzene sulfonamide),4-amino-N-?3-amino-5-carboxylic acid methyl benzene sulfonamide,dehydroxylation?methyl isopropyl oxazole and 4-amino-N-(1-amino-3-methyl propyl benzene sulfonamide.The dominant phylum of different TEA-enriched bacteria groups are similar,mainly including Proteobacteria,Chloroflexi,Bacteroidetes and Actinobacteria.With the increase of acclimation,the abundance of Actinobacteria and Bacteroidetes decreases,while the abundance of Proteobacteria increases.Sulfurospirillum,Diaphorobacte,Geothrix and Geobacter were the dominant strains of the former TAE domestication on the Genus level.The microbial communities of MI and MII increased with the enrichment time.The dominant species of the three TEA species are Desulfomicrobium,Norank c bacteroidetes vadin HA17 and Caldisericum,that is,the species with SO₄^2-as the electron receptor is dominant.With the extension of acclimation period,the richness and diversity of microbial community decreased,and the species composition of the microbial community removed from sewage treatment plants was similar.Under the stress of sulfamethoxazole,the species difference of microbial community appeared.According to the COG functional classification of OUT in MI and MVII,microbial community succession showed phylogeny and metabolic function transfer under long-term sulfamethoxazole stress at high concentration.