Elucidation of the electron transfer mechanisms of hydrogen production from light by Shewanella oneidensis - cadmium sulfide biohybrid system
Catarina M. Paquete, Henrik Hapke, Mónica Martins
Abstract
The biological hydrogen production from sunlight using biohybrid systems is an emergent attractive technology developed to help decarbonize manufacturing, transportation, and energy production. The electroactive organism Shewanella oneidensis MR-1 has been successfully used as a biocatalyst in whole-cell biohybrid systems for hydrogen production. In this work, knock-out mutants of the key proteins involved in the extracellular electron transfer pathway of S. oneidensis MR-1 were used to unravel the electron transfer pathway of the biohybrid S. oneidensis-CdS system for the photoproduction of hydrogen. While the cytochromes OmcA, MtrC, MtrA and CymA were shown to be crucial for electron uptake and hydrogen production, the periplasmic proteins STC and FccA do not participate in this process. This information was used to improve hydrogen production, demonstrating that the photoproduction of hydrogen by a biohybrid system can be improved and can be a promising approach to address global energy and environmental problems.