The Research On The Characteristics And The Expression Of The Key Gene For Phosphorus Removal Of Denitrification Phosphorus Removal Bacteria

Biological phosphorus removal method is widely used for removalingphosphorus of sewage water, in a biological phosphorus removal process the mostimportant factor is phosphorus removal bacteria, so it is necessary to studythecharacteristics of phosphorus removal bacteria for improving the efficiency ofbiological phosphorus removal method.In this paper, denitrification phosphorusremoval bacteria1k1is looked as a starting point, using molecular biology to sdudyits characteristics and the expression of the key gene for phosphorus removal.Firstly, it is the research of the influence of environmental factors on thephosphorus removal ability of1k1,the results are as follows:(1)The pH1k1can accept is ranging from7to9,the optimum pH is7,and whenpH is8or9, the growth of bacteria and phosphorus removal rate are not so differntfrom when the pH is7.(2)The influence on the grown and phosphorus removal rate of the strain is notconsistent whether there is miroelements or not,the relationship between the changeof phosphorus removal efficiency and the bacterial weight.(3)According to the temperature gradient experiment,the influence oftemperature on the grown of the strain is the same as the phosphorus removalrate,this is to say environmental temperature is an important factor in the growth ofmicroorganisms.When the temperature is30℃,the growth of1k1is the best,and so isthe removal rate of PO43--P.When the temperature is40℃,the growth of1k1isweaker.When the temperature is20℃,the growth and phosphorus removal rate arevery bad.This shows that under the experimental conditions the optimum temperaturefor1k1is25~35℃.(4)Different initial concentrations of phosphorus only affect the removal ratePO43--P，the removal of phosphorus is low when the initial concentrations ofphosphorus is high.Judging from the growth of bacteria,bacterial weight is increasingas the addion of the initial concentrations of phosphorus,but the difference is notobvious, so that is to say the phosphorus concentration has little impact on the growthof strains1k1. (5) Different carbon sources results in different paths of the phosphatemetabolism,the paths of PHA synthesis and compositions vary when different carbonsources are used,all of this can effect the efficiency of phosphorus removal. Withsodium acetate as carbon source the phosphorus removal of is best, followed bysodium citrate and mixed carbon source, glucose worst.Sodium acetate can be easilyabsorbed mainly for producing PHB which is used for phosphate metabolism by cellsbecause it is short-chain fatty acids.With sodium citrate as carbon source,the strainsmainly produce PHV, and PHB is little.With glucose ascarbon source get the worstefficiency of phosphorus removal,as the metabolism processes were complex as somestudies showed that glucose—a nonvolatile short chain fatty acids—was firstlyfermented into acetic acid and propionic acid and then absorbed by the DPB.Seeondly,using the NCBI website the relevant in formation and these quenceinformation of DNA of PhoU,ppx,ppk are acqired,whieh are the key enzymes in theproeess of phosphorus removal.Finally,by using the method of moleeular biology,extraeted the genome DNA of1k1,and with the E.coli DH5α as a template amplified the PhoU,ppx,ppk gene by thePCR teehnique.And submitted the gene sequences to NCBI website for thecorresponding serial number.