Three mild halophilic PAO Isolation, identification and characterization phosphorus
|Keywords||hyperhaline wastewater halophilic phosphate accumulating bacteria 16S rDNA phosphate removal capability|
Conventional biological phosphorus removal process is more dominant when operating under a low salinity environment, because high salinity can cause bacterial plasmolysis and loss of metabolic functions. But in some industries, such as fertilizer, petroleum, and seafood process industry and so on, the wastewater contains high concentration of salt. As a consequence it has become an issue for research to screening of heterotrophic PAOs.Using monopotassium phosphate as the sole phosphate source, three strains of halophilic phosphate accumulating bacteria, designated as qdp01, qdp03 and qdp05, were selected after the enrichment and separation of the biological sludge in a stably operated system in which the carbon source was derived from the domestic sewage. According to the morphological observation, physiological biochemical tests and sequence analysis of the 16S rDNA, strain qdp01was identified to be as Alcaliqenes sp. Strain qdp03 and qdp05 were identified to be as Enterbacters sp.Varying salinity, temperature, pH and carbon sources were investigated to identify the optimal conditions for phosphorus removal. The results were as follows:when salinity 2%, temperature 30℃, pH 8.0 and sodium acetate was used as carbon sources, the removal rates of the phosphate by the three strains were all over 80%. Through the experiments about anaerobic/oxic continuous cultivation in SBR reactor, three strains have common nature of PAOs, the phosphare removal rate is higher when the strains were anaerobic/oxic continuous cultivated. The optimal salinity ranges of three strains were 0-5%. So the three strains can tolerant a high ranges of salinity, which have great application value for phosphorus removal of hyperhaline wastewater.