The culture of bacteria

Saraswati Jayanthi

Microbiology is the study of organisms too small to be seen clearly by the unaided human eye. They are less than one millimeter in diameter and must be examined with a microscope. Micro-organisms include bacteria, fungi, algae and protozoans. Microbes occur everywhere in nature – air, water, soil, in plants and animals. They survive even under extreme environmental conditions. Their activities range from enhancement of soil fertility to causing diseases. Given that microorganisms play such an important role in our lives, we can learn a lot from culturing and observing bacteria. However, the cultivating techniques for isolation of microbes require expertise. This article describes some simple ways in which these techniques can be applied in a school classroom.

Soil is a rich source of both organic and inorganic nutrients and is inhabited by numerous micro-organisms such as bacteria, actinomycetes, fungi, algae, and protozoa. The number of bacterial cells per gram of soil can be as high as two billion!! The most common bacteria we can find and isolate from the soil are Bacillus, Pseudomonas, Clostridium, Staphylococcus, Micrococcus, Sarcina, Escherichia coli, Azatobacter, Rhizobium and Streptococcus.

Dr. Saraswati Jayanthi is senior biology teacher and head of the department – sciences at Sreenidhi International School, Aziznagar Campus, Hyderabad. She can be reached at [email protected].

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