Optimization of degradation conditions of polyacrylamide degrading complex bacteria by response surface methodology
In order to solve the environmental pollution caused by PAM,13 polyacrylamide degrading bacteria were isolated from the waste water containing polymer in Daqing Oil Field by enrichment and domestication.The degradation rate was determined by starch cadmium iodide method,and three bacteria A1,E1 and E4 with high degradation rate were screened.They were identified as Bacillus subtilis,Serratia marcescens and Klebsiella aerogenes by morphology and molecular biology.The effects of initial concentration,inoculation amount,different carbon and nitrogen sources and metal ions on the degradation of polyacrylamide by A1E1E4 were studied,and the degradation conditions were optimized by response surface method.The results show that:The composite bacteria A1E1E4 were inoculated into the basic medium containing polyacrylamide with a mass concentration of 300.00 mg/L,NH4C1 with a mass concentration of 569.48 mg/L,glucose with a mass concentration of 709.16 mg/L,and Ca2+with a concentration of 3.57 mmol/L at the inoculation rate of 2%.Under the condition of 30 ℃ for 5 days,the degradation rate reached 61.45%.When the complex bacteria were added into the oilfield containing PAM,the degradation rate reached 93.72%after 70 days,which was 70.84%higher than that of natural degradation.The results provide theoretical basis andtechnical support for bioremediation of PAM polluted environment.