Heterotrophic bacteria accompanying Stichococcus bacillaris in laboratory cultures

The number and composition of bacterial microflora accompanying Stichococcus bacillaris in various media with urea was determined. The number of heterotrophic bacteria during 5 days of incubation increased 10-fold. Only some of the isolated bacterial strains were able to grow in medium for algae supplemented with dead S. bacillaris cells. It is suggested that bacteria utilize organic matter released to the medium by S. bacillaris. The most numerous among the isolated bacteria were Enterobacteriaceae. The order of domination by bacterial populations distinguishes nonaxenic cultures of S. bacillaris from cultures of other algae.