Screening,Identification And Degradation Conditions Of A Bisphenol A-degrading Bacterium

Bisphenol A(BPA)is a kind of classic endocrine disrupter which has the activity of estrogen.Therefore,it can lead to some serious consequences such as human-body precocity,endocrine dyscrasia,destruction to health of fetuses or children,even cancer and so on.Since BPA is one of synthetic chemical substances,it is widely used in every aspect including articles for daily supplies and light industry as an important kind of chemical materials in modem times.For example,BPA is one of the raw materials of children's feeding-bottles.If BPA leaks out during the progress of production or the residue was used by mistake,BPA will cause some pollution in every respect of water,soil and air.BPA also can enter into the human body through the food chain and food web,and then it leads to many bad effects when BPA's content is beyond the limitation.Because of the perniciousness of BPA,the solution of the pollution is more and more valued for the past few years.The traditional physical and chemical processing method of dealing with bisphenol A has some limitations,leading to the results that sometimes it can not meet the requirements,so the biodegradation method is more and more valued,which has advantages both in treatment effect and running cost,and it has a perfect developing prospect.7 strains that have the stronger ability of BPA degradation(more than 40%)of the 25 bisphenol A degradating strains,which were isolated from activated sludge in the aeration tank of Shenyang northern sewage treatment plant,were named as D-03?D-06?D-11?D-14?D-17?D-22 and D-23.A high-efficiency bisphenol A degradating strain D-17,which could utilize BPA as carbon source for growth,was isolated from the 7 strains.According to 16 S rDNA gene sequence,morphological,physiological and biochemical analysis,the strain D-17 was identified as Acinetobacter calcoaceticus.The degradation conditions tests of strain D-17 showed that the optimal conditions for BPA degadating strain D-17 were initial optimum content of pH 7.0,inoculum 10%,rotary speed 150 r/min,temperature 30 ? and time 5d.The degradation rate of BPA was 52.62% at the initial BPA concentration of 60 mg/L.The maximum tolerated concentration of strain D-17 to nitrobenzene was 140 mg/L.Moreover,the degradation rate reduced to 40.37% with an addition of glucose.However,the addition of Na2HPO4+KH2PO4 and peptone could increase the degradation rate to 60.01% and 57.15% respectively.