CANCELED - CEE Seminar: Enzyme-vault Nanocatalysts for Biodegradation of Water Contaminants

Abstract: Vault nanoparticles are classified as ribonucleoproteins with highly conserved barrel cages, which are large enough to efficiently package and deliver macromolecules. While binding to solid matrices can enhance longevity of free enzymes, it can limit substrate diffusion and decrease reaction rates.  Vaults are plausible candidates to package enzymes and other molecules in benign vehicles for sustaining biosynthesis or biodegradation without the need for frequent replenishment. Recombinant vaults, packaged with various components or containing various modifications at the cap and/or waist, are being tested for use in the medical field to reduce the growth of lung tumors and prevent infections, and for cell targeting and drug delivery. We recently developed highly active manganese peroxidase (MnP) and laccase encapsulated in vaults for biodegrading water pollutants like phenol, triclosan, 1,4-dioxane, bisphenols, nitrotoluenes, synthetic dyes, and per-and polyfluoroalkyl substances (PFASs). The enzymes packaged in vaults showed significantly higher thermal stability and contaminant degradation rates than the unpackaged enzymes. By immobilizing vault-packaged enzymes into sol-gels, the enzymatic stability was further improved. The vault shells elegantly templated mesoporous silica and also prevented enzymes from being inactivated by the gelation conditions. The vaults are being custom produced on a large scale and incorporated in a variety of reactor designs. Since vaults occur in nature and have been isolated from many eukaryotes, including humans, their application is unlikely to cause risks for human health as well as the environment.

Bio: Shaily Mahendra is a professor and Samueli Fellow in the UCLA Department of Civil and Environmental Engineering, and a member of the California NanoSystems Institute, Institute of the Environment and Sustainability, and the Molecular Toxicology Program. She received her doctorate from UC Berkeley. Mahendra has developed enzyme-vault nanocatalysts for water purification, omics-based tools for environmental assessments, antifouling coatings for medical and environmental applications, energy-positive wastewater treatment approaches, and abiotic and biological transformation of emerging contaminants, including 1,4-dioxane, PFASs, pesticides, munitions, dyes and bisphenol analogs. She received the CH2M-Hill/AEESP Outstanding Doctoral Dissertation Award, NSF CAREER Award, DuPont Young Professor Award, Northrop Grumman Excellence in Teaching Award, Hellman Fellowship, Poptech Science and Public Leadership Fellowship, Faculty Mentor Award, AEESP Distinguished Service Award, Walter Huber Civil Engineering Research Prize and Paul Busch Award from the Water Research Foundation. She is an editor of the Journal of Hazardous Materials and co-editor-in-chief of JHM Letters.