Illustrative image only. Actual product may vary.Aleksandrow Agar
Also known as：Aleksandrov Agar · Aleksandrov Medium · Potassium Solubilizing Bacteria Agar · KSB Agar
For the isolation and detection of potassium-solubilizing bacteria from soil and rhizosphere samples.
- Category
- Dehydrated Culture Media
- Dissolve per litre
- 29.61 g
- Pack sizes
- 500 g · 5 kg · 25 kg
Data updated：2026-11-07
Overview
Aleksandrow Agar is an agar (solid) medium. It is insoluble potassium mineral as the potassium source; used to screen potassium-solubilising bacteria by clearing zone. STBIO manufactures it from food-grade raw materials in an ISO 22000 certified facility, with a COA for every batch.
Principle
Potassium is one of the most abundant elements in soil, but the majority is locked within insoluble minerals such as feldspar and mica, leaving little in a plant-available form. Certain soil bacteria are able to release potassium from these minerals and play an important role in soil fertility and plant growth.¹ʼ² In Aleksandrow Agar, potassium aluminium silicate serves as the sole, insoluble source of potassium, which most organisms cannot utilize directly. Dextrose provides the carbon and energy source, magnesium sulphate and ferric chloride supply essential ions, tricalcium phosphate provides phosphorus, and calcium carbonate contributes to the buffering of the medium. Potassium-solubilizing bacteria secrete organic acids such as citric, oxalic, tartaric, and gluconic acid, which dissolve the insoluble potassium minerals. As a result, these organisms produce a clear halo zone around their colonies on the otherwise hazy (opaque) agar, providing a visual indication of potassium solubilization.²
Directions
Suspend 29.6 g of the powder in 1 L of purified water. Heat with continuous stirring and bring to the boil for 1 minute. Sterilize by autoclaving at 121°C for 15 minutes. Cool to 45–50°C. Mix well to evenly suspend the insoluble minerals and pour into sterile Petri plates. Test the finished medium for performance using stable, standard control cultures.
Cultural response
| Test organism | ATCC | Growth |
|---|---|---|
| Bacillus mucilaginosus | good-luxuriant | |
| Bacillus circulans | 4513 | good-luxuriant |
| Escherichia coli | 25922 | good |
Product highlights
- Manufactured to the standard formulation, 29.61 g per litre
- Performance verified against standard control strains before release (Bacillus mucilaginosus, Bacillus circulans, Escherichia coli)
- Available in 500 g / 5 kg / 25 kg, from laboratory to industrial scale
- COA, specification sheet, and technical data sheet available; samples on request
- Manufactured in Taiwan with reliable supply
Frequently asked questions
01How much powder per litre?
Use 29.61 g per litre of deionised water; preparation and sterilisation conditions are given on the specification sheet.
02Which organisms is it suitable for?
Bacillus mucilaginosus, Bacillus circulans, Escherichia coli. See the cultural response table and the specification sheet.
03How is this product prepared?
Suspend 29.6 g of the powder in 1 L of purified water. Heat with continuous stirring and bring to the boil for 1 minute. Sterilize by autoclaving at 121°C for 15 minutes. Cool to 45–50°C. Mix well to evenly suspend the insoluble minerals and pour into sterile Petri plates. Test the finished medium for performance using stable, standard control cultures.
04How do I request a bulk quotation, and can you provide a COA?
Yes. This product is available in 500 g, 5 kg, 25 kg. Tell us your application and volume when requesting a quotation; we reply within one working day and can supply the COA, specification sheet, and technical data sheet.
Used in these applications
References
- 1. Aleksandrov V. G., 1958. Organo-mineral fertilizers and silicate bacteria, Doklady Akademii Nauk.
- 2. Sheng X. F. and He L. Y., 2006. Solubilization of potassium-bearing minerals by a wild-type strain of Bacillus edaphicus. Canadian Journal of Microbiology, 52:66–72.