Screening And Application Of Tetracycline Degrading Bacteria

Tetracycline antibiotics are a kind of low-cost broad-spectrum antibiotics,and they are one of the most widely used and most used antibiotics in the world.However,due to the large amount of tetracycline used in the breeding process of animal husbandry,the absorption is low,and the unabsorbed tetracycline is excreted by the breeding animals into the environment,resulting in a large amount of antibiotic residues and accumulation in the environment.There are many methods to remove tetracycline in the environment,but the use of microbial degradation to degrade tetracycline has become an important means and research hotspot for the degradation of tetracycline because of its low processing cost and no secondary pollution.In this study,a strain capable of efficiently degrading tetracycline was selected from the activated sludge of pig farms,and six possible degradation products of tetracycline were captured by LC-MS.Degradation of tetracycline and growth and reproduction under the environment of tetracycline concentration and inoculation amount.The results of the study are as follows:Use LB medium for enrichment culture,separation and purification,and preservation of bacterial species.Use inorganic salt medium as the medium for tetracycline concentration detection and culture for the sole carbon source.Three strains were selected from the sludge of pig farms and purified for many times.Among strains with degradability,TC-Sh2 has the best degradation effect on tetracycline,has the ability to efficiently degrade tetracycline,and can grow and reproduce with tetracycline as the only carbon source.According to the physiological and biochemical identification,the strain is Pseudomonas.The possible degradation products and possible degradation pathways of tetracycline were analyzed by LC-MS.Six possible degradation products of tetracycline by this strain were captured,namely C11H10O4?C14H8O2?C19H17O5?C15H16O4?C18H30O6 and C11H7NO10,The main pathways for the degradation of tetracycline by the degrading bacteria TC-Sh2 are demethylation(-CH3),dehydroxylation(-OH),decarbonylation(-C=O-)and oxidation formation.The degradation efficiency and growth and reproduction of the degrading strain TC-Sh2 under different conditions of pH,temperature,tetracycline concentration and inoculum amount were determined,and its degradation characteristics and growth characteristics were studied,and the best conditions for the strain to degrade tetracycline were found It is in an environment of pH 9,37? 100 mg/L tetracycline concentration and 3%inoculum,and according to the experimental results,it is found that the OD600 value of the degrading strain TC-Sh2 is the same as that of the degrading strain TC-Sh2 on tetracycline.The degradation effect has a certain connection.The possibility of degradation of tetracycline in water by the degrading strain TC-Sh2 was speculated.The results of this study show that the tetracycline-degrading bacteria TC-Sh2 has a good degradation effect on tetracycline,and has the application potential of using microorganisms to repair tetracycline pollution and environmental treatment technology.