Self-sustaining microalgae-laden hydrogel enables high-efficiency biomass production.

Engineered living materials integrated with photosynthetic microalgae represent an attractive exploration for sustainable biomanufacturing, as these systems couple light-driven biomass production and CO2 assimilation. However, the translation of these systems toward next-stage applications remains largely constrained by the lack of scalable and resource-efficient implementation strategies. Here, we report a biogenic microalgae-laden hydrogel (BMH) platform fabricated via extrusion-based 3D bioprinting for efficient biomass production with improved spatial utilization. Compared to conventional liquid cultivation, the self-sustaining hydrogel system formulated from natural polysaccharides and nutrient medium enables homogeneous cell distribution at centimeter scale under continuous illumination, and enhances the biomass accumulation of Chlorella sp., a fast-growing edible microalga, by 4.35-fold. Transcriptomic analyses reveal coordinated upregulation of genes associated with photosynthesis pathways, elucidating the molecular mechanism for improved light harvesting and carbon assimilation. This study establishes an efficient platform for high-density microalgal cultivation with scalability potential, advancing the design of photosynthetic living materials and opening new opportunities for sustainable biomanufacturing in food and energy fields.