A De Novo Auto-Activated Solar-Driven Biohybrid System for Hydrogen Production in Methanotrophic Cells

Climate change driving by greenhouse gas emissions from petroleum-based energy has garnered significant attention. Renewable energy production via a sustainable system that integrates the cell factory and visible-light-driven photocatalysts offers a novel approach for upcycling methane and addressing global energy challenges. Here, an auto-activated biohybrid system driven by solar energy is developed for converting methane into hydrogen fuel, which incorporated thienoviologen (S-MV²⁺) and genetically engineered methanotrophic bacteria. In this system, S-MV²⁺ functioned as photosensitizer and electron mediator, capturing solar energy and supplying electrons for an enzyme-catalyzed bioprocess. The genetically modified Methylomicrobium buryatense 5GB1 mutant, lacking methanol dehydrogenase but overexpressing hydrogenase, is able to convert methane into methanol that maintains the electron flow cycle by quenching photogenerated holes for both hydrogen biosynthesis and methane oxidation. Finally, the highest H₂ production of 272.96 μM from this biohybrid system was achieved with methanol as a sacrificial agent generated by the H₂-producing mutant, resulting in a 140-fold enhancement. This innovative method showcases the potential of coupling photocatalysis with methanotrophic biocatalysis for sustainable energy production. Additionally, the system introduces a new strategy for self-regeneration of sacrificial agents, offering a promising avenue for hydrogen production using greenhouse gases in an eco-friendly manner.