Study On The Denitrifying Capability、Morphological Plasticity And Adaption To Unrelated Carbon Source Of Strain P.Putida PAO-1

The removal of nitrogen and phosphorus is the key to solve the eutrophication problem. The denitrifying phosphorus removal, combing biological dephosphorization and biological denitrification in together, has very good prospects for research and application. Denitrifying phosphorus accumulating organisms（DPAOs） are widely studied on dephosphorization and denitrification characteristics, but the objects are usually confined to mixed microbes, the researchs on related properties of pure culture strains are limited relatively.More over, it is not hard to find studys on phosphorus accumulating by filamentous organisms, and studys on carbon source of denitrifying phosphorus removal. But there is limited research on deformation characteristics of phosphorus accumulating organisms（PAOs） and utilization to related carbon source of non-volatile fatty acids（NVFAs） such as toluene、phenol and amino acid by PAOs up till nowAs the research object, strain P.Putida PAO-1 was isolated from lab-scale alternating anaerobic/aerobic biological filter and preserved at 4 ℃ in our laboratory, its denitrification capability, morphological plasticity and adaption to unrelated carbon source such as toluene、phenol and L-leucine were studied. The conclusions are as follows:（1） Strain P.Putida PAO-1 was tested for its potential denitrification with synthetic wastewater. The soluble chemical oxygen demand（SCOD） was removed by 83.95% with the removal rate of 17.26 mg/（g·h）, the soluble orthophosphate（SOP）was released by 51.47% with the rate of 0.64 mg/（g·h） and the P/C was 0.039 g P/g SCOD. Strain P.Putida PAO-1 could absorb phosphorus under both aerobic and anoxic conditions, with phosphorus absorption rate of 59.46% and 1.04 mg/（g·h） under aerobic condition, 32.89% and 0.60 mg/（g·h） under anoxic condition, respectively. The concentration of NO₃^－-N had little effect on phosphorus absorption by strain P.Putida PAO-1 under anoxic condition. Both NO₃^－-N and NO2--N could be electron acceptor for denitrifying phosphorus removal. But when NO₃^－-N was electron acceptor, the phosphorus removal rate was significantly higher than that of the NO2--N as electron acceptor.（2） Morphology growth and phosphorus removal rate of strain P.Putida PAO-1 under different p H、temperature and salinity conditions were analyzed. For the growth of strain P.Putida PAO-1, the optimal p H、temperature and salinity were 30 ℃、7.0 and 0 g/L, respectively. Under the condition with the optimal p H、temperature and salinity, phosphorus removal rate reached to 33%. By the analysis of the individual cell lengths under the growth with different p H、temperature and salinity, a conclusion that strain P.Putida PAO-1 had morphological plasticity was drawn.（3） The adaption to unrelated carbon source for strain P.Putida PAO-1 was studied. For the infusibility of toluene, 5% of Twain 20 was added as solubilizer in preparation culture with toluene as the sole carbon source. Toluene could be metabolismed by strain P.Putida PAO-1 as the sole carbon source. When the concentration of toluene was 0.088 g/L, short adaption phase was observed, the growth of P.Putida PAO-1 entered the decline directly, with the final ramoval rate of 71.2%. When the concentration of toluene was 0.176 g/L, strain P.Putida PAO-1 grew rapidly and short adaption phase was observed. The concentration change was consistent with the trend of growth curve, with the final ramoval rate of 81.4%. When toluene concentration was 0.352 g/L, adaption period and stable period were short, the trend of concentration change was consistent with its growth curve mainly, with the final ramoval rate of 72%. In addition, neither phenol nor L-leucine could be utilized by strain P.Putida PAO-1.