Photosynthetic organisms convert sunlight, CO₂, water, and mineral nutrients into energy-rich organic compounds and oxygen, forming the foundation of life on Earth. Beyond their natural role, algae and cyanobacteria can be harnessed for the sustainable production of valuable biochemicals. These organisms can host synthetic metabolic pathways and enzymes, enabling them to act as microbial cell factories that produce and secrete targeted solar fuels and chemicals. However, the economic feasibility of solar-driven aquatic bioproduction faces significant challenges, including self-shading (which limits light utilization), high water consumption, and the energy demands of mixing. Additionally, for efficient and continuous production, microbial biocatalysts must be long-lived and optimized for secretion and product recovery.

To address these limitations, we encapsulate photosynthetic cells within biocompatible polymeric hydrogels to create photosynthetic engineered living materials (ELMs). This transformation from suspension culture to structured material offers a protective and stable environment for cells, improving their longevity and performance. In case studies, cyanobacterial and algal cells immobilized in thin, photocurable hydrogel layers via 3D printing achieved superior production titers and space–time yields compared to conventional systems. These ELMs, especially when fabricated using renewable materials and scalable printing techniques, hold strong promise for advancing the sustainability and efficiency of biomanufacturing in the chemical industry.