Study On Screening And Degradation Characteristics Of Highly Efficient Antibiotic Degradation Strains

Antibiotics are not only used for human beings,but also used for disease prevention and treatment of livestock and aquaculture,agricultural pest control,aquaculture and feed,in China and many countries in the world.With the widespread use of antibiotics,Asia has become the largest antibiotic market in the world.China has ranked first in the global antibiotic production and export.Residual antibiotics enter the environment through a variety of different ways,and the water and soil are polluted to varying degrees.At present,the general treatment processes and remediation technologies are relatively difficult to remove antibiotics,and the amount of antibiotics in the environment is gradually increasing.Microbial degradation is a commonly used water treatment and environmental remediation technology,but most of the microorganisms selected in existing studies are targeted at one antibiotic,and most of them are suitable for freshwater environment.By antibiotics as the only carbon source medium,from the mangrove ecosystem screening,enrichment and salinity and antibiotic concentration gradient domestication,isolation and screening of a single strains of tetracycline,oxysultracycline,sulfamethoxazole,enrofloxacin and norfloxacin and other antibiotics have degradation,can adapt to the high salt environment of highly efficient strains;The dominant strains were identified,the optimal growth conditions were determined,and their degradation properties were investigated.Phylogenetic analysis by gene sequence,After isolation and identification,the result showed that 37 degrading strains were from 12 different genus.Among them,the dominant genus were Bacillus sp.,Pseudomonas sp.,Herbaspirllum sp.,accounting for 40.54%,16.22% and 16.22%,respectively.A total of 30 fungi strains were isolated and identified from 4 different genus.Among them,Talaromyces sp.,Penicillium sp.and Aspergillus sp.accounted for 23.33%,30% and 43.33%,respectively.Through the influence of the selected strains on microbial growth,the optimal growth conditions of bacteria and fungi were p H7.0,30℃,and the loading amount was 100 m L;Two strains with high microbial activity in each genus were identified as the dominant strains,with a total of 12 strains;Salinity acclimation and adaptation experiments of the dominant strains showed that bacteria and fungi were domesticated from 3.4 ‰ of environmental conditions to 34 ‰ of seawater salinity.Antibiotic domestication tolerance experiments with the dominant strains showed that the highest tolerance concentrations for tetracycline,sulfa,and quinolone antibiotics reached 150 mg/L,300 mg/L,and 300 mg / L,respectively.Under optimal growth conditions,the 3 days showed that 12 dominant strains were able to degrade 6 antibiotics,and 81% of tetracyclines,sulfonamides and quinolones were 81%,80%,60% and 74%,60% and 71%,respectively.After application research,in the screening of bacterial strains,Bacillus strains also have a good removal effect on ammonia nitrogen,COD and phosphorus in the simulated mariculture wastewater,and the removal rate can reach more than 60%;In the selection of fungal strains,the selected strains have good removal effect on ammonia nitrogen,COD and phosphorus.The removal rate of ammonia nitrogen and COD can reach more than 85%,the removal rate can reach 94%,the removal rate of phosphorus is more than 29%,and the removal rate can reach 54%.