Abstract

The production of weak organic acids by microorganisms has been attributed as the prime reason for the solubilization of insoluble phosphates under both in vitro and soil conditions. Literature seems to be heavily biased towards gluconic acid production by microbes and its subsequent release into the environment as the key factor responsible for phosphate solubilization. This has found credibility since gluconic acid being a product of the Kreb’s cycle is often detected in large quantities in the culture media, when assayed under in vitro conditions. In the present work, the organic acid profiles of four elite phosphate solubilising isolates were determined in the presence of different insoluble sources of phosphates, under in vitro buffered culture conditions by HPLC (High-Performance Liquid Chromatography). While most previous studies did not use a buffered culture media for elucidating the organic acid profile of phosphate solubilizing bacterial isolates, we used a buffered media for estimation of the organic acid profiles. The results revealed that apart from gluconic acid, malic acid is produced in significant levels by phosphate solubilizing bacterial isolates, and there seems to be a differential pattern of production of these two organic acids by the isolates in the presence of different insoluble phosphate sources.

Highlights

  • Phosphorus is an essential nutrient for plant growth and reproduction

  • Phosphate solubilizing potential of the bacterial strains Among four strains Paraburkholderia tropica P-31 released the highest levels of soluble P (50.0 μg/ml) when tricalcium phosphate (TCP) was used as insoluble source of phosphorus and drop in pH was observed from 7.0 to 4.4

  • This study has shown that under in vitro buffered condiitons apart from gluconic acid, malic acid is produced in significant levels by the Gram negative phosphate solubilizing bacterial isolates belonging to various genera

Read more

Summary

Introduction

Phosphorus is an essential nutrient for plant growth and reproduction. Phosphorus is available in soil primarily in organic or inorganic forms, but most forms are not available for plant uptake due to its tendency to form complexes with cations such as Calcium (Ca) in alkaline soils and Aluminum (Al) and Iron(Fe) in acidic soils. Several studies have advocated the use of biological formulations to overcome P deficiency in soil. Many rhizospheric microorganisms have been reported to solubilize mineral phosphates by different mechanisms. The most commonly encountered phosphate solubilizing bacterial genera are Pseudomonas, Bacillus, Rhizobium and Enterobacter. Their ability to solubilize phosphates has been mainly attributed to their organic acid secretion potential[1, 2]

Methods
Results
Conclusion
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call