Solubilization of insoluble potassium and phosphate by Paenibacillus kribensis CX-7: A soil microorganism with biological control potential

From wheat field soil samples of Chang’an, Shanxi, seven multifunctional strains with the ability of solubilizing phosphate and potassium were isolated for its utilization as a biological fertilizer, and the most efficient strain named CX-7 was chosen for further study. CX-7 was identified as Paenibacillus kribbensis after a series of physiological and biochemical experiments, morphological observation and 16S rRNA gene sequence analysis. The solubilization ability of CX-7 was tested in the condition of pure culture. The results show that 71.60 mg/L and 5.18 mg/L water-soluble phosphorus and 3.44 mg/L potassium can be released from phosphate powder, lecithin and potassium feldspar powder, respectively which means that CX-7 had the high degradation rate on inorganic phosphorus. Antagonistic experiment showed that CX-7 strain had widely antagonism against pathogenic microorganism (cotton yellow wilt pathogen, cotton wilt pathogen, wheat root rot diseases pathogen, wheat scab pathogens and Pestalotiopsis microspora). This suggests that the stain has potential for further evaluation for its use as a biological fertilizer and biological control regent.   Key words:  Paenibacillus kribbensis, phosphate solubilization, potassium solubilization, biological control regent.