Phosphate Solubilizing Microorganisms.pptx

Introduction to Phosphate solubilizing Microorganisms

1. PHOSPHATE SOLUBILIZING MICROORGANISMS Dr. B. KARUNAI SELVI ASS OCIATE PROFESSOR OF B OTANY V.V.VANNIAPERUMAL COLLEGE FOR WOMEN VIRUDHUNAGAR- 626 001 TAMIL NADU, INDIA [email protected]

2. PHOSPHATE SOLUBILIZING MICROORGANISMS Phosphorus is an essential macronutrient for growth and development of plants It is involved in important metabolic pathways like photosynthesis, biological oxidation, nutrient uptake and cell division (Illmer and Schinner, 1992).

3. Worldwide soils are supplemented with inorganic P as chemical fertilizers to support crop production But repeated use of fertilizers deteriorates soil quality (Tewari et al., 2004). Phosphates present in soil are made available to plants mainly by the activities of some soil microorganisms The are called Phosphate Solubilizing Microorganisms (PSM).

4. Phosphorus occurs in soil in two forms, organic phosphates and inorganic phosphates Application of phosphate-solubilizing microorganisms increases the soil fertility PSM have ability to convert insoluble P to soluble P by releasing organic acids, chelation and ion exchange

5. The availability of iron in soil decreases with increase in pH and therefore PSM function better in neutral and alkaline soils than in acid soils . Phosphorus may also be made more available for plant uptake by certain bacteria that release hydrogen sulphide (H 2 S). a product that reacts with ferric phosphate to yield ferrous sulphide , liberating the phosphorus.

6. Ferric Phosphate Mobilization Solubilisation of phosphate usually requires acid production. In flooded soil, the iron in the form of insoluble ferric phosphate FP reduced to soluble iron with a concomitant release of phosphorus into solution.

7. Mineralization: Conversion of Organic Phosphorus into Insoluble Inorganic Phosphates Many soil microorganisms produce enzymes that attack many of the organic phosphorus compounds in the soil and release inorganic phosphate. This process is comparable to the mineralization of organic nitrogen compounds . The enzymes involved in these reactions are collectively called ‘phosphatases’ which have a broad range of substrate specificity.

8. Solubilization : Conversion of Insoluble Inorganic Phosphates into Soluble Inorganic Phosphates The availability of phosphorus depends on the degree of solubilization by various organic and inorganic acids produced by microorganisms in soil. These are the solubilized form of insoluble inorganic phosphates which are taken in by the plants .

9. Fungi, e.g., Aspergillus, Penicillium, Fusarium are the most important of the soil microorganisms which produce substantial amounts of these acids; others are the bacteria, namely, Bacillus, Pseudomonas, Micrococcus, Flavobacterium , etc

10. List of fungi (PSM) Sl. No. Organism 1 Aspergillus flavus 2 Aspergillus niger (strain- 1) 3 Aspergillus fumigatus 4 Aspergillus niger (strain- 2) 5 Trichoderma viride 6 Chaetomium globosum 7 Fusarium solani 8 Aspergillus ustus 9 Aspergillus versicolor 10 Mucor circinelloides 11 Aspergillus carneus 12 Aspergillus restrictus 13 Aspergillus erythrocephalus

11. Microscopic view of the fungal species isolated from the municipal solid waste and used for phosphate solubilizing activity Aspergillus flavus Aspergillus fumigatus Trichderma viride Fusarium solani

12. Aspergillus niger (Strain – 1) Aspergillus niger (Strain – 2) Chaetomium globossum Aspergillus erythrocephalus

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