Solar-hybrid biocatalyst for methane hydroxylation to methanol

Area of Science:

• Biocatalysis and Green Chemistry
• Renewable Energy Conversion
• Greenhouse Gas Mitigation

Background:

• Methane hydroxylation offers a sustainable route to methanol production but faces challenges due to the inert C-H bond in methane.
• Natural methane conversion by methane monooxygenase occurs under ambient conditions, utilizing NADH and a reductase.
• Existing biocatalytic systems often require cofactors, limiting cost-effectiveness and scalability.

Purpose of the Study:

• To develop an NADH-independent biosolar platform for efficient and sustainable methane hydroxylation.
• To design a system that directly utilizes light energy to activate methane monooxygenase.
• To enhance methanol production yields under ambient conditions.

Main Methods:

• Engineered a biosolar platform integrating a xanthene-based light harvester with hydroxylase.
• Facilitated direct photoexcited electron transfer from the light harvester to the enzyme's diiron active site.
• Investigated the effect of halogenation on xanthene derivatives to optimize electron transfer kinetics.

Main Results:

• Achieved direct electron transfer from the light harvester to the hydroxylase active site, eliminating the need for NADH or reductase.
• Demonstrated a methanol time yield of 7.52 mmol g_cat^-1 h^-1 using the NADH-free photobiocatalytic system.
• Showcased enhanced electron transfer efficiency through halogenation of the xanthene light harvester.

Conclusions:

• The developed NADH-free biosolar platform enables solar-driven biocatalytic methane hydroxylation under ambient conditions.
• This approach offers a promising, cost-effective, and sustainable strategy for methanol biomanufacturing.
• The design concept provides a blueprint for future solar-powered biocatalytic conversions.