Pringsheim’s Medium

Pringsheims Medium is recommended for the cultivation of Blue Green Algae.

Composition**

**Formula adjusted, standardized to suit performance parameters

Directions

Suspend 0.24 grams in 1000 ml distilled water. Heat if necessary to dissolve the medium completely. Dispense and sterilize by autoclaving at 15 lbs pressure (121°C) for 15 minutes.

Principle And Interpretation

Soil algae are ubiquitous in nature wherever moisture and sunlight are available. They are visible to the unaided eyes in the form of a green scum on the surface of soils. By virtue of the presence of chlorophyll in their cells, algae are photoautotrophic and use carbon dioxide from the atmosphere and liberate oxygen. The blue-green algae contain a pigment known as phycocyacin in addition to chlorophyll which imparts a special blue green colour to these organisms. Some of the blue-green algae possess specialized cells known as heterocysts which are implicated in nitrogen fixation. The water logged rice soil provides an ideal environment for the growth of certain blue-green algae.

Blue green algae are very important organisms for the health and growth of many plants. They are one of very few groups of organisms that can convert inert atmospheric nitrogen into an organic form, such as nitrate or ammonia. Blue green algae include a large number of widely distributed species. Inspite of their vigorous growth under natural conditions, only a few of these organisms have been cultured in artificial media (1). Pringsheims Medium is recommended for the cultivation of Blue Green Algae (2).

It is not easy to isolate pure cultures of algae since several species of algae are covered by mucilaginous matrix which harbours many contaminants. Serial dilutions of soil are made and 1 ml aliquots of each dilution transferred into suitable sterilized liquid medium either in flasks plugged with cotton wool or in bottles filled with sterilized white sand moistened with the algal medium. The flasks or bottles are kept for a few weeks near a source of light. Individual colonies are then transferred to agar slants for identification (3).

Potassium nitrate and ammonium hydrogen phosphate in the medium provide nitrogen source. Ferric chloride provides an iron source to blue green algae. Magnesium sulphate and the chloride salts are sources of ions that simulate metabolism.

Quality Control

Appearance
White to cream homogeneous free flowing powder

Colour and Clarity
Colourless clear solution over a white precipitate

Cultural Response
M698: Cultural characteristics observed after an incubation at 25-27°C for 1 week .

Storage and Shelf Life

Store below 30°C in tightly closed container and the prepared medium at 2 - 8°C. Use before expiry date on the label.

Reference

1. Gerloff G. C., George P., Fitzgerald and Folke Song, The Mineral Nutrition of Coccohloris peniocystis., Am. J. of Botany, Vol. 37, No. 10, 1950, pg 835 840.
2. Pringsheim E. G., 1964, Pure cultures of Algae, Their Preparation and Maintenance, Hafner Publishing Co, New York and London.
3. Subba Rao N. S.,1977, Soil Microorganisms and Plant Growth, Oxford and IBH Publishing Company