Robust strategy for bioplastic production from cyanobacteria-enriched microbiomes: insights from gene expression and population dynamics

• Evaluated PHB production in 4 cyanobacteria microbiomes by dual-phase over 168 days. • One microbiome achieved 26% PHB, surpassing the 12–15% dcw of the other three. • Low-PHB microbiomes overexpressed the gene for a key enzyme in the TCA cycle. • Microbiome with high PHB showed overexpression of gene phaC . • High-PHB microbiome overexpressed the encoding PHB synthase gene. • Microbiome with high PHB showed balanced cyanobacteria/alphaproteobacteria composition.