Screening and Characterization of Highly Efficient Phosphorus Solubilizing Bacteria in Ecologically Fragile Areas

Abstract Ecological fragile areas are facing the problems of soil degradation and vegetation reduction due to the damage of ecosystem caused by natural or human factors. In order to solve these ecological problems, microbial remediation technology has become a hot spot in research and practice because of its environmental protection and high efficiency. In this study, we screened high-efficient phosphate-solubilizing strains from ecologically fragile regions, and analyzed their phosphate-solubilizing characteristics and environmental adaptability. The aim of this study is to explore the suitable microbial remediation methods for ecological vulnerable areas, in order to provide scientific basis and technical support for ecological restoration in these areas. The physical and chemical properties of soils in ecologically fragile regions were comprehensively analyzed to assess their fertility status and nutrient deficiency. Functional microorganisms capable of degrading phosphorus were screened from the soil and identified by 16S rDNA. The growth characteristics and adaptability of these phosphate-solubilizing bacteria were investigated by simulating different salt concentrations and pH conditions in order to evaluate their potential in practical application. The results showed that the soil fertility in this ecologically fragile region was low, and it lacked key nutrients such as organic matter, nitrogen and phosphorus. Three phosphate-solubilizing strains were screened and identified as Pseudomonas aeruginosa, Pseudomonas soil and Pseudomonas alkylphenolica. After three days of incubation, the phosphate solubilization amounts were 183.2 mg/l, 102.6 mg/L and 84.1 mg/L, respectively. W1 strain grew best in neutral environment and had good tolerance to pH=6, but had poor adaptability to alkaline and high-salt environment. Y7 had a wide range of pH adaptability, but its growth was limited under pH=9 and high salinity. Y12 strain grew best at pH=6 and could tolerate alkaline environment at pH=9, but was sensitive to the change of salt concentration. Although all three strains of phosphate-solubilizing bacteria screened in this study have the ability of phosphate-solubilizing, however, there are significant differences in growth characteristics and environmental adaptability, which provides a theoretical basis and technical support for the application of microbial remediation technology in ecological vulnerable areas.