Isolation, identification, and characterization of a phosphate-solubilizing bacterial strain

Abstract:

[Background] Most of the phosphorus in the soil exists in the form of insoluble phosphate, which is unavailable to crops, and traditional chemical fertilizer causes environmental pollution. [Objective] To tackle soil phosphorus deficiency and develop a safe and efficient microbial fertilizer. [Methods] An efficient phosphate-solubilizing bacterial strain was screened out from the soil behind the library of Wuhan University of Science and Technology and identified by morphological observation, determination of physiological and biochemical indexes, and 16S rRNA gene sequencing. The phosphate-solubilizing conditions were optimized based on NBRIP medium, and the phosphorus-solubilizing mechanism was explored by high performance liquid chromatography. [Results] The strain was identified as Burkholderia gladioli. Among the 20 amino acids, D-methionine was prominent in promoting the growth and phosphate solubilization of the strain, improving the growth and solubilized phosphate by 19.09% and 16.16%, respectively. Sodium formate inhibited the growth and phosphorus dissolution of the strain, with the inhibition rate of 39.08% and 10.66%, respectively. The strain dissolved phosphate in the environment by secreting organic acids such as glucuronic acid and D-L-malic acid. The fertilizer prepared with the strain could significantly promote the growth of pepper seedlings. [Conclusion] B. gladioli secretes organic acids to dissolve phosphate in the soil, which lays a theoretical basis for the preparation and application of biological fertilizer.