Integration of genetically engineered algal light antenna proteins on semiconducting metal oxide substrates for enhanced sensor signal generation and for light harvesting in photoelectrochemical cells

• Research unit: COST
• Project number: C13.0083

Key words (English)

covalent attachment; metal oxide; semiconductor; photoelectrochemistry; solar hydrogen

Research programs (English)

COST-Action TD1102 - Photosynthetic proteins for technological applications: biosensors and biochips (PHOTOTECH)

Short description (English)

Phycocyanin is a light harvesting protein in blue-green algae and has been found to increase the photocurrent density of hematite photoanodes when attached to it. Covalent attachment with a di-imidazole linker molecule further increased the photocurrent density. Recent engineering of the system phycocianin-hematite yielded further enhancement when the phycocyanin was genetically modified by functionalising it with a hexahistidine tag. In the proposed project, we will target the engineering of this bio-hybride assembly by understanding the physico-chemical origins of the light-induced interaction beween protein and hematide, and making sensor and energy conversion devices.

Abstract (English)

The principal scientific and technological problem that we wanted to address in this project was the covalent attachment of photosynthesis proteins onto metal oxide semiconductor photoelectrodes. We started with an affinity based interaction, specifically the design of a poly-Histidine-tagged protein and a corresponding hematite-binding (Hem-tag) protein. This approach is successful for direct functional loading of more proteins on the photoelectrode surface, than without the 'tagging' strategy. From the experiments we conducted it turned out that a strategy of combining His-tagged CPC with melanin as binder showed a higher photocurrent. The role of the melanin and the function of His-tagged or Hem-tagged CPC is not yet understood at the molecular level. We made encouraging progress and success with method development in this cross-disciplinary research field. This includes the laccase-test, which enhances the biocatalytic performance of the enzyme. Pioneering experiments were done with synchrotron based resonant valence band photoemission spectroscopy targeting the interface of CPC and biofilms on photoelectrodes in wet, electrified and illuminated conditions. Within a COST STSM short stay scientific mission at SCK-CEN we investigated the photoelectrochemicasl properties of a biofilm during Y-irradiation.

References in databases (English)

Swiss Database: COST-DB of the State Secretariat for Education and Research Hallwylstrasse 4 CH-3003 Berne, Switzerland Tel. [phone] Swiss Project-Number: C13.0083