The Research On Screening Of Ofloxacin Degrading Bacteria And Study On Its Removal Performance

Ofloxacin is an effective antibiotic that has been detected in soil and water environment to varying degrees in recent years due to human misuse.Microbial degradation is an inherent way to degrade organic matters in the ecosystem.It has a good prospect for removing antibiotic residues in the environment owing to its wide application range,low input cost and high output efficiency.In order to study the removal efficiency of Ofloxacin,a strain was screened from the residual activated sludge of municipal wastewater treatment plant by using environmental biotechnology,and its growth characteristics and degradation performance were analyzed,the preliminary application study was also carried out.This study can provide a theoretical and practical basis for the treatment of residual antibiotics in the environment.The main findings are as follows:1.A strain of ofloxacin-degrading bacteria was screened,it was named OF01,and it was liminarily identified as Alcaligenes.2.The suitable growth conditions and characteristics of OF01 were studied in this paper:The growth of OF01 accords with Logistic growth curve,at the 5th hour OF01 gets into logarithmic growth period,and at the 15th hour OF01 gets into stable growth period,at the 26th hour OF01 gets into twilight period.The strain grows well in the temperature range from 25℃ to 35℃,the pH range from 6 to 8 in LB liquid medium,the concentration range from 0 to 20 g/L of salt,the inorganic available carbon and the liquid loading range from 100 to 150 mL.3.The performance of OF01 for Ofloxacin removal was studied in this paper:The rule of strain growth and Ofloxacin removal is that the strain grew rapidly on the 3rd to 6th day,and the ability of Ofloxacin removal is strong,the strain begins to grow slowly on the 7th day,the maximum biomass and removal rate reaches 63.79%on the 10th day,after which the bacteria died,the removal rate is basically unchanged.The amount of OF01 has no significant effect on the removal rate.It is economical to select 10%(V/V).The highest removal rate is 65.16%when the initial concentration of Ofloxacin is 15 mg/L.When the culture temperature is 30℃ the maximum removal rate is 63.92%.OF01 can tolerate weak acidity and weak alkalinity,the removal rate of OF01 under neutral condition is the highest(63.17%).The removal rate by adding inorganic quickacting carbon source is much better than that by using Ofloxacin as single carbon source.OF01 has strong salt tolerance.When the salt concentration is 5 g/L,the removal rate of OF01 is 63.91%.The effect of shaking liquid volume on removal rate is small.The optimal combination was as follows:the initial Ofloxacin concentration was 15mgl,the temperature was 30℃ the pH was 7,the salt concentration was 5 g/L,the inoculation amount was 10%(VV)the carbon source was sodium acetate,and the filling volume was 100 mL.4.Preliminary application of OF01 in simulated aquaculture wastewater:OF01 has significant removal efficiency for COD,ammonia nitrogen,TP and Ofloxacin in low concentration of Ofloxacin wastewater,the respective removal rates are 81.19%,67.27%,74.48%and 58.09%,the results shows that the strain has the potential to treat aquaculture wastewater.