Liquid Metal Nanobiohybrids for High-Performance Solar-Driven Methanogenesis via Multi-Interface Engineering.

Area of Science:

• Materials Science
• Biotechnology
• Renewable Energy

Background:

• Conventional semiconductor nanobiohybrids for solar-driven methanogenesis face limitations in tunability and biocompatibility.
• These limitations lead to instability and reduced methane (CH4) selectivity due to spontaneous electron and proton transfer.

Purpose of the Study:

• To engineer advanced nanobiohybrids for efficient and stable solar-driven methanogenesis.
• To overcome the limitations of traditional semiconductor-based systems by utilizing liquid metal alloys.

Main Methods:

• Integration of eutectic gallium-indium (EGaIn) liquid metal alloys with Methanosarcina barkeri (M. b) to form M. b-EGaIn nanobiohybrids.
• Characterization of the nanobiohybrids, focusing on the self-limiting oxide layer formed on EGaIn and its interaction with the microbial component.
• Analysis of methane yield, selectivity, and long-term stability under solar irradiation.

Main Results:

• The M. b-EGaIn nanobiohybrids achieved a maximum CH4 yield of 455.64±15.99 μmol g⁻¹.
• Demonstrated long-term stability over four successive 7-day cycles with >99% CH4 selectivity.
• Observed enhanced proton-coupled electron transfer at the core-shell interface, facilitated by increased hydrogenase expression.

Conclusions:

• The developed M. b-EGaIn nanobiohybrids represent a significant advancement in solar-driven methanogenesis.
• Multi-interface engineering of nanobiohybrids offers a promising strategy for sustainable CO2-to-biofuel conversion.
• This approach enhances structural stability and CH4 selectivity, addressing key challenges in the field.