Projects per year
Abstract
Light-driven enzymatic catalysis is enabled by the productive coupling of an enzyme to a photosensitizer. Photosensitizers used in such hybrid systems are typically costly, toxic and/or fragile, with limited chemical versatility. Carbon dots (CDs) are low-cost nano-sized light-harvesters that are attractive photosensitizers for biological systems as they are water-soluble, photostable, non-toxic and their surface chemistry can be easily modified. We demonstrate here that CDs act as excellent photosensitizers in two semi-biological photosynthetic systems utilizing either a fumarate reductase (FccA) for the solar-driven hydrogenation of fumarate to succinate, or a hydrogenase (H2ase) for reduction of protons to H2. The tunable surface chemistry of the CDs was exploited to synthesize positively charged ammonium-terminated CDs (CD-NHMe2+), which were capable of transferring photo-excited electrons directly to the negatively charged enzymes with high efficiency over 24 h. Enzyme-based turnover numbers of 6000 mol succinate (mol FccA)−1 and 43 000 mol H2 (mol H2ase)−1 were reached after 24 h. Negatively charged carboxylate-terminated CDs (CD-CO2–) displayed little or no activity and the electrostatic interactions at the CD–enzyme interface were determined to be essential to the high photocatalytic activity observed with CD-NHMe2+. The modular surface chemistry of CDs together with their photo-stability and aqueous solubility make CDs versatile photosensitizers for redox enzymes with tremendous scope for their utilization in photobiocatalysis.
Original language | English |
---|---|
Pages (from-to) | 16722–16730 |
Number of pages | 9 |
Journal | Journal of the American Chemical Society |
Volume | 138 |
Issue number | 51 |
Early online date | 28 Nov 2016 |
DOIs | |
Publication status | Published - 28 Dec 2016 |
Profiles
-
Julea Butt
- School of Biological Sciences - Professor of Biophysical Chemistry
- Centre for Molecular and Structural Biochemistry - Member
- Centre for Photonics and Quantum Science - Member
- Chemistry of Life Processes - Member
- Chemistry of Light and Energy - Member
- Energy Materials Laboratory - Member
- Molecular Microbiology - Member
Person: Research Group Member, Research Centre Member, Academic, Teaching & Research
Projects
- 1 Finished
-
Advancing Biotechnologies for Fuel Generation: Exploiting Transmembrane Cytochromes for Solar Energy Conversion
Butt, J., Clarke, T., Richardson, D. & Lyall, V.
Biotechnology and Biological Sciences Research Council
30/06/13 → 29/06/16
Project: Research