Azotobacter Agar (Sucrose)

Intended Use

Recommended for isolation, cultivation and identification of sucrose positive Azotobacter species from soil.

Composition**

Final pH (at 25°C): 7.2±0.2

**Formula adjusted, standardized to suit performance parameters

Directions

Suspend 36.67 grams (the equivalent weight of dehydrated medium per litre) in 1000 ml of purified / distilled water. Heat to boiling to dissolve the medium completely. Sterilize by autoclaving at 15 lbs pressure (121°C) for 15 minutes. Cool to 45-50°C. If slight precipitate occurs after autoclaving distribute it evenly before pouring into sterile Petri plates.

Principle And Interpretation

Bacteria of the family Azotobacteraceae constitute the majority of heterotrophic free-living nitrogen fixing bacteria (4). Azotobacter is a genus of free-living diazotrophic bacteria which have the highest metabolic rate compared to any other microorganisms. Azotobacters have generated a good deal of interest in the scientific community because of their unique mode of metabolism, by which they can fix nitrogen aerobically. Azotobacter Agar (Sucrose) is used for isolation and cultivation of sucrose positive Azotobacter species from soil (3).

Type of specimen

Soil samples.

Specimen Collection and Handling

For soil samples, follow appropriate techniques for sample collection, processing as per guidelines and local standards (4). After use, contaminated materials must be sterilized by autoclaving before discarding.

Warning and Precautions

Read the label before opening the container. Wear protective gloves/protective clothing/eye protection/ face protection. Follow good microbiological lab practices while handling specimens and culture. Standard precautions as per established guidelines should be followed while handling specimens. Safety guidelines may be referred in individual safety data sheets.

Limitations

1. Some species may show poor growth due to nutritional variations.

Performance and Evaluation

Performance of the medium is expected when used as per the direction on the label within the expiry period when stored at recommended temperature.

Quality Control

Appearance: Off white to beige homogeneous free flowing powder

Gelling: Firm, comparable with 1.5% Agar gel

Colour and Clarity of prepared medium: Yellow coloured, clear to slightly opalescent gel with a slight precipitate forms in Petri plates.

Reaction: Reaction of 3.67% w/v aqueous solution at 25°C. pH : 7.2±0.2

pH: 7.00-7.40

Cultural Response

Cultural characteristics observed after an incubation at 25-30°C for 24-48 hours.

Storage and Shelf Life

Store between 10-30°C in a tightly closed container and the prepared medium at 20-30°C. Use before expiry date on the label. On opening, product should be properly stored dry, after tightly capping the bottle in order to prevent lump formation due to the hygroscopic nature of the product. Improper storage of the product may lead to lump formation. Store in dry ventilated area protected from extremes of temperature and sources of ignition Seal the container tightly after use. Product performance is best if used within stated expiry period.

Disposal

User must ensure safe disposal by autoclaving and/or incineration of used or unusable preparations of this product. Follow established laboratory procedures in disposing of infectious materials and material that comes into contact with sample must be decontaminated and disposed of in accordance with current laboratory techniques (1,2).

Reference

1. Isenberg, H.D. Clinical Microbiology Procedures Handbook 2nd Edition.
2. Jorgensen, J.H., Pfaller, M.A., Carroll, K.C., Funke, G., Landry, M.L., Richter, S.S and Warnock., D.W. (2015) Manual of Clinical Microbiology, 11th Edition. Vol. 1.
3. Pelczar M. Jr., 1957, Manual of Microbiological Methods.
4. Subba Rao N. S., 1977, Soil Microorganisms and Plant Growth, Oxford and IBH Publishing Co., New Delhi.