Enzymes are exquisite catalysts for chemical synthesis, capable of providing unparalleled levels of chemo-, regio-, diastereo- and enantioselectivity. Unfortunately, biocatalysts are often limited to the reactivity patterns found in nature. In this talk, I will share my groups efforts to use light to expand the reactivity profile of enzymes. In our studies, we have exploited the photoexcited state of common biological cofactors, such as NADH and FMN to facilitate electron transfer to substrates bound within enzyme active sites. In other studies, we found that enzymes will electronically activate bound substrates for electron transfer. In the presence of common photoredox catalysts, this activation can be used to direct radical formation to enzyme active sites. Using these approaches, we are able to develop biocatalysts to solve long-standing selectivity challenges in chemical synthesis.
Guest speakers
Dr. Todd Hyster
Professor at Cornell University
Developing Biocatalysts for the 21st Century
Biography
Todd is a native of Apple Valley, Minnesota, and did his undergraduate studies at the University of Minnesota. In 2008 he joined Tomislav Rovis' group at Colorado State University for his graduate studies to develop Rhodium-catalyzed C–H activation reactions. During his Ph.D., Todd did an internship with Thomas Ward at the University of Basel where he prepared an artificial metalloenzyme for an asymmetric C–H activation reaction. After graduating, he joined the group of Frances Arnold at Caltech as an NIH Postdoctoral Fellow. In the Arnold group, Todd evolved P450s to catalyze nitrene transfer reactions. In 2015 he started his independent career at Princeton University and in 2021 moved to Cornell University, where he is currently an Associate Professor of Chemistry and Chemical Biology. Todd’s group has developed photochemical strategies to expand the synthetic utility of common enzymes, enabling them to address long-standing selectivity challenges in the chemical synthesis literature.
Dr. Geoffrey Ozin
Professor at the University of Toronto
Save the World – Shining Light on CO2
Energy makes the world go round, we have plenty of it, and it is mainly fossil sourced. In 2020 we used 23,000 TWh, that’s the good news, the bad news is that the 40 billion tons of CO2 emitted into our atmosphere from its production, distribution, and use is now posing an existential threat to life on earth, and it is getting worse. The latest IPCC report flags ‘code red’ for humanity, unless we act fast. The solution is simple on paper but complex in practice; transition from fossil to renewable forms of energy using known technologies that work, can be scaled, implemented over a decade or so, and go global. While not a panacea, one approach to help ameliorate climate change, is to decarbonize the fossil powered and fossil sourced chemical and petrochemical industries using CO2 as the feedstock. Manufacturers of hundreds of millions of tons of chemicals and fuels, these industries would not exist without catalysts; more than 90% are heterogeneous, their production represents a $8.5 billion per year market, and the gross annual sales of chemicals synthesized by catalysis is $3 trillion. Currently, most of these catalytic processes are driven by fossil heat and are responsible for about 2.3 billion tons of CO2 emissions, about 5.8% of global greenhouse gas emissions. Syngas, a fossil derived mixture of CO and H2, is a primary feedstock for hundreds of thousands of commodity chemicals and many transportation fuels. Commercially available technology exists, for making syngas from CO2 and H2O feedstocks, mainly driven by heat, thermochemically. Why not power them with light, photochemically? In this presentation I will look what is around the bend in this emerging field, especially the most recent focus on how to engineer high photon efficiency photocatalysts and photoreactors to produce solar syngas, a sustainable feedstock for solar chemicals and fuels.
Biography
Geoffrey A. Ozin is a Distinguished University Professor at the University of Toronto and Tier 1 Government of Canada Research Chair in Materials Chemistry and Nanochemistry. He currently spearheads the Solar Fuels Group at the University of Toronto. He has held positions as Honorary Professor at The Royal Institution of Great Britain and University College London, External Adviser for the London Centre for Nanotechnology, Alexander von Humboldt Senior Scientist at the Max Planck Institute for Surface and Colloid Science and the Center for Functional Nanostructures at the Karlsruhe Institute of Technology, and Global Chair at Bath University. He is the author of four books: Nanochemistry: A Chemical Approach to Nanomaterials (RSC 2006), Concepts of Nanochemistry (Wiley-VCH 2009), The Story of CO2: Big Ideas for a Small Molecule (UTP 2020), and Energy Materials Discovery Enables a Sustainable Future (RSC 2021), and recipient of many National and International Awards, recent ones include World Cultural Council Albert Einstein science Prize, World Technology Network Energy Prize, Royal Society of Chemistry Centenary Award. He lives with his wife in Toronto, Canada.
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