The Screening Of Copper And Chromium-resistant Strains And The Optimization And Characteristics Of Copper Adsorption Conditions

With the improvement of the level of urbanization and industrialization,and heavy metal pollution sources increasingly serious.The heavy metal pollution seriously affects the regional ecological development and food safety issues related to the development of national economy,especially the agricultural sustainable development,it has attracted extensive attention of the society.During the NPC and CPPCC sessions in 2016,environmental pollution problems caused by a lively discussion of all walks of life.Follow the environment governance,emphasis on addressing environmental problems in the development,control of pollution from the source.The methods of heavy metal pollution treatment are mainly divided into physical,chemical and biological methods.As traditional physical,chemical treatment methods are costly and complicated to operate,the effect of instability and other shortcomings.Currently,because of its low cost,high efficiency and environmental advantages of the microbiological method increasing people's attention,it has became so hot.Therefore,in order to tap the efficient microbial strains for the treatment of heavy metal pollution,we isolated and screened copper-resistant,chromium-resistant microorganisms from the sample of USA.Study on optimization of adsorption conditions and characterization.The results showed that:?1?183 strains isolated from samples,after a preliminary screening,there are 4strains resistant to copper,they are strain HDZK-NTF22,HDZK-NTF45,HDZK-NTF46,HDZK-NTF47;1 strain resistant to chromium,it is strain HDZK-NTB1;?2?The strain HDZK-NTF22 and strain HDZK-NTF45 were identified as Penicillium chermesinum;strain HDZK-NTF46 identified as Aspergillus fumigatus;strain HDZK-NTF47 identified as Penicillium Oxalicum,By morphology and ITS gene sequencing analysis.The highest tolerance value is 200mmol/L,200mmol/L,200mmol/L,250mmol/L.?3?Through morphological observation,physiological and biochemical tests and16S rDNA analysis,strain HDZK-NTB1 was identified as Acinetobacter baumannii.The highest tolerance value is 370mmol/L.?4?Copper-resistant strain HDZK-NTF47 optimum adsorption conditions,the culture temperature is 23?,the culture time is 18h,the culture medium is pH 7,the medium volume is 150mL/500mL.At this time,Cu²⁺absorption rate?80.22±2.95?%,up to 46.87%than before?Before the optimization is?33.35±2.56?%?.?5?Study heavy metal resistance test on the copper-resistant strain HDZK-NTF47.The result shows that it has good tolerance on Pb²⁺,Zn²⁺and Cr⁶⁺.Pb2⁺tolerance value reached 300mmol/L,Zn²⁺tolerance value reached 150mmol/L and Cr⁶⁺tolerance value of 30mmol/L;?6?Study heavy metal salt tolerance test on the copper-resistant strain HDZK-NTF47.The result showed that it ban be able to resist variety of heavy metal salt mixture effectively,but compared with the control treatment without metal salt,the growth rate of the bacteria was low.