Pure Cultures of Algae from Soil

The soil is a habitat for both autotrophic and heterotrophic micro flora. ' In a majority of cases, the latter outnumber the former many times, and attempts to separate the autotrophs from other organisms usually result in failure. Occasionally it may be desirable to have available in pure culture small autotrophic chlorophyll-bearing plants. These lend themselves readily to experimental conditions. Large numbers may be grown in a small space at comparatively little expense, and it might be desirable at times to study such plants in pure culture conditions. An easy method of obtaining algae free from contamination is highly desirable. This article describes, a method that has been employed for this purpose. The procedure consists in employing a selective medium for the.algae, a subsequent enrichment of the cells by incubation, a differential separation of cells, and finally, a plating on a solid medium. The selective medium for this purpose consists of any nutrient solution in which the algae will grow and which contains no organic carbon. The following was employed in this work: