THE ISOLATION, PURIFICATION, AND NUTRIENT 



SOLUTION REQUIREMENTS OF 



BLUE-GREEN ALGAE 



GERALD C. GERLOFF, GEORGE P. FITZGERALD, 

 and FOLKE SKOOG 



University of Wisconsin, Madison, Wisconsin 



Introduction 



Although some species of blue-green algae produce serious 

 nuisance blooms and growths in reservoirs, lakes, and streams, 

 surprisingly little is known of their exact nutritional require- 

 ments. This undoubtedly is due in part to the difficulties that 

 have been encountered in growing many of these organisms in 

 pure culture, a point stressed in a recent publication by Rodhe 

 (1948). It is true that a few blue-green algae have been cultured 

 for many years, for example, species from die family Nostocaceae 

 in studies on nitrogen-fixation (Fogg, 1947), but to our knowl- 

 edge the principal bloom-producers, such as Microcystis aerugi- 

 nosa Kiitz. Elenkin, Aphanizomenon flos-aquae (L.) Ralfs and 

 Gloeotrichia echinulata (J. E. Smidi) Richter, have not been suc- 

 cessfully grown in artificial media for extended periods. 



For this reason, a project was started in the botany department 

 of the University of Wisconsin in 1947, as part of a general pro- 

 gram of Lakes and Streams Investigations at the University, 

 with the purpose of accumulating basic data on the nutritional 

 requirements and physiology of blue-green algae. It was consid- 

 ered essential first to isolate a number of species in bacteria-free 

 cultures, for only with pure cultures would the data obtained 

 be specific for the algae. 



This paper will report the procedures used and progress made 

 in isolating, purifying from bacteria, and culturing representa- 

 tive species of these organisms. The results of experiments on 



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