Fatty acid profiling: its usefulness in the evaluation of microbial associations with the green microalga Apatococcus...

To determine differences in microbial community structures, fatty acids from two strains of the green microalga Apatococcus constipatus were isolated and identified by instrumental means. The main fatty acids found were 16:0 and 14:0. These predominant acids represented more than 53% of the total fatty acid (content in both algal isolates. In addition, saturated fatty acids were present in much greater quantity than unsaturated ones. Differences between the strains in the composition of other, modified fatty acids were also evident. The occurrence of fatty acid biomarkers characteristic of certain taxonomic groups confirmed the presence of Gram-positive and Gram-negative bacteria, and fungi. Those observed variations were undoubtedly due to distinct community structures of symbiotic microorganisms living in close associations with the alga. The results presented here indicate that different isolates of the same alga might exhibit different microbial community structures.