| Phosphorus is a nutritional limiting factor.The large amount of phosphorus-containing wastewater discharge,resulting in increasingly serious eutrophication of water and the broken phosphorus cycle of nature,accelerating the accumulation of phosphorus in marine sediments,causing a global phosphorus crisis.Research has confirmed that marine bacteria play an important role in the natural phosphorus cycle,can induce the formation of metallic ore and phosphate rock.The research on the screening and application in wastewater of highly efficient phosphorus removal bacteria isolated from the oceans is still rare and at the initial stage.To explore strains with wide range of environmental adaptation and special phosphorus removal mechanism,can provide a variety of microbial resources for the treatment of refractory organic wastewater and salt wastewater,as well as the recycling of heavy metals with low concentration.Currently,the biological phosphorus removal mainly concentrates on the enhanced biological phosphorus removal of phosphorus accumulating organisms.But high salt environment can inhibit the growth of microorganisms,bring down the phosphorus removal efficiency greatly.And salt-tolerant sludge acclimation period is very long and the process of start-up is difficult.Therefore,utilizing marine bacteria which grows in saline environment directly is more economic and efficient.The biomass and best phosphorus removal efficiency of 619 strains from South China Sea were determined.By statistical analysis,the distribution curve of phosphorus removal efficiency was negative spike distribution,with generally good phosphorus removal effects of strains.The average best phosphorus removal efficiency is 83.95%and the strains which best phosphorus removal efficiency reached more than 90%accounted for 48.63%.And Erythrobacter,Alteromonas,Pseudoalteromonas,Marinobacter accounted for most in the strains with a phosphorus removal efficiency more than 90%.The best phosphorus removal effect of the strains was independent of the depth,temperature and pH of the sampling environment,which was mainly determined by the cell structure and metabolic process of the bacteria.There was a significant positive correlation between the optimum phosphorus removal rate and OD600 when controlling depth,temperature and salinity.The best phosphorus removal efficiencies among efficient phosphorus removal strains from the surface seawater and the sediments have a significant difference.Experiment selected surface water strains Erythrobacter sp.F1-0-01,Alteromonas sp.13-0-47 and sediment strains Pseudoalteromonas sp.E422-1,Marinobacter sp.70-23,four highly efficient phosphorus removal strains,as representative strains of the follow-up study.Effects of salinity,pH and temperature on bacteria growth and phosphorus removal efficiency were analyzed.Compared with phosphorus accumulating bacteria,the growth and phosphorus removal range of marine strains were wider,which would have broad application prospects in low temperature,high salt,strong acid and alkali wastewater phosphorus removal fields.The surface seawater and sediment strains can grow at salinity of 0?7%,temperature of 5?35 ?,pH 5?10,but the optimum growth and phosphorus removal range of each strain were different.Surface water strains Erythrobacter sp.F1-0-01 and Alteromonas sp.have good phosphorus removal effects at a salinity range of 0?3%and 0?5%.The adaptive range of sediment strains Pseudoalteromonas sp.E422-1 and Marinobacter sp.70-23 to the salinity is more extensive.And the effluent with a salinity range between 0 and 7%has good phosphorus removal effect with E422-1 and 70-23,which can be applied to high-salinity wastewater.Four strains can withstand the impact of pH change within a certain range,and have a certain ability to adjust the pH.When the pH was between 7 and 9,the four strains were well grown with the phosphorus removal efficiency above 95%.At pH 5 or 10,Erythrobacter sp.F1-0-01 and Marinobacter sp.70-23 still have good growth and phosphorus removal efficiency,which reflect the wide adaptability of two strains to pH.The surface seawater strain Alteromonas sp.13-0-47 and the sediment strains Pseudoalteromonas sp.E422-1 and Marinobacter sp.70-23 have a wide range of adaptability to temperature and high phosphorus removal efficiency,which can be applied to the actual treatment of low temperature wastewater.Erythrobacter sp.strain F1-0-01 can achieve good growth and phosphorus removal effect in the range of 15?35?.When the temperature is low,the growth and phosphorus removal effect of the strain are obviously inhibited.The phosphorus absorbed by the strain was firstly used to meet its own growth and then would be used for the synthesis of EPS.Compared with the surface seawater strain,the sediment strain was more capable of secreting EPS.When there was excess phosphorus in the solution,the EPS on the surface of the sediment strain could further adsorb phosphorus in the solution with a relatively high pH,and then might combine with the metal ions to form metal phosphate precipitate.The phosphorus absorbed by the cell of the surface seawater strain was mainly accumulated on the cell membrane,while that of the sediment strain was more accumulated in the cell.The phosphorus in EPS of four strains is in the form of phosphate monoester,the main form of D-glucose-6-phosphate.In this paper,the biomass and phosphorus removal effect of 619 strains of South China Sea were analyzed statistically.The general situation of phosphorus removal effect of strains in the South China Sea was generally understood.The similarities and differences of the mechanism of phosphorus removal between the surface seawater strains and sediment strains were explored,which provides a new idea for biological phosphorus removal mechanism. |
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