a culture containing cells of a single species of microorganism.

The most reliable way of isolating a pure culture is from a single cell of a population. For yeast and microscopic fungi, this is accomplished by Lindner’s drop technique. Drops from a cellular suspension of yeast or fungi spores (conidia) are transferred to a cover glass, or cover slip. The cover glass is then placed over a cavity slide. Microscopic techniques are used to find a drop containing a single cell, and the drop is then transferred, using sterile procedures, to a culture medium. Pure, single-cell bacterial cultures are isolated with the aid of a micromanipulator or thin capillaries (B. V. Perfil’ev’s microselector).

The isolation of pure cultures is necessary in the classification and study of the variability of microorganisms and in the production of vaccines. It is also used in the microbiological industry for the preparation of enzymes, antibiotics, vitamins, steroid hormones, and other preparations.