The structure and diversity of microalgae-microbial consortia isolated from various local organic wastes

Pure microalgae cultivation in organic wastes may be hampered by their low adaptation to extreme growth conditions and by the risk of microbial contamination. This work aimed to isolate self-adapted microalgae-microbial consortia able to survive in organic wastes characterized by extreme conditions, to be then proposed for technological application in removing carbon and nutrients from wastes' streams. To do so, sixteen organic wastes with different origins and consistency were sampled. Twelve microbial consortia were isolated from wastes and their eukaryotic and prokaryotic compositions were analyzed by next generation sequencing. Eight eukaryotic communities were dominated by Chlorophyta, led by Chlorella, able to survive in different wastes regardless of chemical-biological properties. Tetradesmus, the second most represented genus, grew preferentially in substrates with less stressing chemical-physical parameters. Chlorella and Tetradesmus were mostly isolated from cow slurry and derived wastes which proved to be the best local residual organic source.