Infection with intracellular parasite Amoeboaphelidium protococcarum induces shifts in associated bacterial communities in microalgae cultures

Abstract In recent years microalgae products have developed increasing market demand, but sustainable industrial production is still challenged by biological stability of large-scale plants. Yet the relationships between algal hosts, associated microbiomes, and contaminants in photobioreactors remains widely understudied. The aim this study was to investigate temporal development microbiomes four freshwater species Scenedesmus vacuolatus , Desmodesmus quadricauda Chlorella sorokiniana Botryococcus braunii presence absence zoosporic parasite Amoeboaphelidium protococcarum . To compare effects sterile nonsterile culture conditions, infection experiments were performed laboratory (sterile) simulated conditions (open). Algal growth (dry weight, optical density, nutrient consumption) observed for 21 days, samples microbiome collected bacterial 16S rRNA gene Illumina MiSeq sequencing. Infection patterns A. algae species-specific, irrespectively conditions. Bacterial community analysis demonstrated distinct stable communities each species, which mostly dominated ?- ?-Proteobacteria. Upon aphelid parasitosis, diversity increased, compositions diverged algae-specific over time. Moreover, functional traits shifted detoxification, degradation, cellulolysis once infected. This provides a first insight into close connection algae, appearing photobioreactor systems.