PRODUCTION OF AXENIC CULTURES OF MICROMONAS-PUSILLA (PRASINOPHYCEAE) USING ANTIBIOTICS

Bacteria-free cultures of the prasinophyte Micromonas pusilla (Butcher) Manton and Parke, UTEX LB 991, were produced by initially determining the effects of several antibiotics on the growth of this alga and then using a combination of these antibiotics to eliminate associated bacteria. Micromonas pusilla was resistant to penicillin G, neomycin, gentamicin, and streptomycin at bactericidal concentrations but sensitive to chloramphenicol and polymixin B. Passage of M. pusilla through the sequence of antibiotics penicillin G --> neomycin --> gentamicin --> kanamycin resulted in an axenic culture of M. pusilla. This method should be suitable for producing axenic cultures of other strains of M. pusilla.