16S (V3-V4) metabarcoding sequencing of a 15-strain SynCom in co-culture with Prymnesium parvum under nitrogen, phosphorus and vit-B12 limitation, at day 0, 3, 7 and 14 of the co-culturing experiment for the Blueremediomics-coculture project, 2024

Microalgal-bacterial interactions are central to nutrient cycling and ecosystem functioning, yet the mechanisms structuring these associations within marine microbiomes under defined nutrient constraints remain poorly resolved. We used 16S rRNA gene metabarcoding to assess how nitrogen, phosphorus, and vitamin B12 limitation influence the composition and stability of the bacterial community associated with Prymnesium parvum. The objective of this metabarcoding analysis was to quantify shifts in bacterial relative abundances across nutrient regimes. Samples were obtained from controlled laboratory cultures of P. parvum grown alone or with the SynCom under three nutrient regimes: N-limited, P-limited, and B12-limited. Culture samples (10 or 25 mL) were collected on days 0, 3, 7, and 14 of the experiment and filtered through either 3 m or 0.2 m filters. Genomic DNA was extracted following Nucleospin plant II protocol. The V3-V4 region of the 16S rRNA gene was amplified with universal primers and sequenced on an Illumina platform.