The determination of specific phosphatmobilizing activity of soil microorganisms

Abstract

The study aimed to compare the phosphate-mobilizing activity of 69 strains of the genus Bacillus on agar and liquid Muromtsev medium to identify a possible correlation between them. Research methods: microbiological, laboratory-analytical, and statistical. The main results of the study. The closeness of the relationships between the activity of phosphates dissolving on agar and liquid nutrient media by strains of the genus Bacillus have been determined. There is no significant correlation between the size of the dissolution zone on the agar medium and the phosphorus removal in the culture fluid in a liquid medium has been found. However, the correlation coefficients between specific indicators - specific phosphate-mobilizing activity in a liquid nutrient medium (the ratio of the total quantity of dissolved phosphorus to the amount of grown biomass) and specific phosphamobilizing activity on agar medium (the ratio of the zone dimensions of dissolution to the colony size) - is considerable: for the first group = 0.603; for the second group R = 0.752; for the third group R = 0.864; for the fifth group, R = 0.732. The correlation coefficient has an average value (0.415) for the fourth group, includes strains with high phosphate-mobilizing activity (museum strains B. subtilis 54, B. subtilis 72, B. subtilis 101s, B. subtilis 100), as well a new isolated from the soil strains of Bacillus sp. D-31 and D-32. There is a close correlation (R3 = 0,670) between two specific indicators: specific phosphate-mobilizing activity on agar medium (Kr) and specific activity of FMP dissolution in liquid medium (Asp.). (Analysis has conducted taking into account all investigated strains of bacilli). Conclusions. The new indicator of specific phosphate-mobilizing activity use will simplify the screening of strains on agar medium.