Phosphate solubilization and acid phosphatase activity of Serratia sp. isolated from mangrove soil of Mahanadi river delta, Odisha, India

Abstract

Phosphorus is an essential element for all life forms. Phosphate solubilizing bacteria are capable of converting phosphate into a bioavailable form through solubilization and mineralization processes. Hence in the present study a phosphate solubilizing bacterium, PSB-37, was isolated from mangrove soil of the Mahanadi river delta using NBRIP-agar and NBRIP-BPB broth containing tricalcium phosphate as the phosphate source. Based on phenotypic and molecular characterization, the strain was identified as Serratia sp. The maximum phosphate solubilizing activity of the strain was determined to be 44.84 μg/ml, accompanied by a decrease in pH of the growth medium from 7.0 to 3.15. During phosphate solubilization, various organic acids, such as malic acid (237 mg/l), lactic acid (599.5 mg/l) and acetic acid (5.0 mg/l) were also detected in the broth culture through HPLC analysis. Acid phosphatase activity was determined by performing p-nitrophenyl phosphate assay (pNPP) of the bacterial broth culture. Optimum acid phosphatase activity was observed at 48 h of incubation (76.808 U/ml), temperature of 45 °C (77.87 U/ml), an agitation rate of 100 rpm (80.40 U/ml), pH 5.0 (80.66 U/ml) and with glucose as a original carbon source (80.6 U/ml) and ammonium sulphate as a original nitrogen source (80.92 U/ml). Characterization of the partially purified acid phosphatase showed maximum activity at pH 5.0 (85.6 U/ml), temperature of 45 °C (97.87 U/ml) and substrate concentration of 2.5 mg/ml (92.7 U/ml). Hence the present phosphate solubilizing and acid phosphatase production activity of the bacterium may have probable use for future industrial, agricultural and biotechnological application.

Biosolubilization of phosphorus from rock phosphate and other P fertilizers in response to phosphate solubilizing bacteria and poultry manure in a silt loam calcareous soil

“…We were able to detect only two acids from the PSBs, i.e., oxalic acid and gluconic acid. The PSBs isolates used in this study were less effective in producing organic acids in number and amount compared to those reported by other workers (Vyas and Gulati, 2009;Yin et al, 2015;Behera et al, 2017).…”

Plant growth-promoting rhizobacteria able to improve NPK availability: selection, identification and effects on tomato growth

“…Determination of the available P in solution showed that the 15 strains evaluated were able to solubilize the phosphate of the tricalcium phosphate Ca3(PO4)2, ranging from 84.4 to 308.6 mg L -1 . Several studies have reported that many isolates do not produce any visible halo zone on the agar plate, but they can solubilize several types of insoluble inorganic phosphate in liquid medium (Behera et al, 2017). This may be due to varying diffusion rates of different organic acids secreted by different microorganisms.…”

Phosphate Solubilization by <i>Bacillus subtilis</i> and <i>Serratia marcescens</i> Isolated from Tomato Plant Rhizosphere

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