Phycosphere microbiome dynamics in filamentous algae: community composition, stability, and patterns across cultivation scales in phycoremediation systems

Summary

Algae can be used to recover nutrients from municipal wastewater as biomass. This approach supports a more circular use of resources, but it also exposes algae to highly diverse microbial communities that may influence productivity and cultivation stability. This thesis investigated the bacterial communities associated with filamentous green algae used in wastewater treatment. Across laboratory and pilot-scale experiments, many bacteria remained associated with the algae even after prolonged exposure to wastewater communities. Different algal cultures often shared similar groups of bacteria; however, they differed in the specific bacterial strains they contained. These differences were influenced by both the history of the algal cultures and the algae themselves. Together, these findings show that the bacterial communities present in stock algal cultures can have lasting effects on the bacterial communities that develop during wastewater treatment. This supports further research into whether algal microbiomes are steerable and whether this could help improve the management of algal cultivation systems used for wastewater treatment and biomass production.