Elman, T.; Isaac, S.; Yacoby, I.

Microalgal hydrogen production driven by solar energy offers significant promise as a sustainable energy alternative, yet remains economically challenging due to issues of scalability from laboratory to industrial applications. Here, we demonstrate scalable hydrogen production at semi-industrial volumes using the Chlamydomonas reinhardtii pgr5 mutant, employing an optimized cultivation protocol and photobioreactor design. This approach achieves a fivefold increase in hydrogen yield. Notably, the post-production biomass maintains a high-quality protein and nutrients profile, emphasizing microalgae as a "green coin" with energy security on one side and food security on the other. Techno-economic analysis suggests, achievable hydrogen production costs could reach $2.70/kg H2 under projected improvements, and potentially decrease furthur to $1.48/kg with full optimization. By effectively bridging laboratory research and practical industrial implementation, our study establishes a dual-purpose algal hydrogen production platform aligned with circular economy principles, positioning microalgae prominently within sustainable energy and food frameworks.