Seunghyun Sim
University of California-Irvine, CA·Chemistry·Early-career
Enzymes are nature's catalysts: proteins that speed up chemical reactions with remarkable precision. Industry would like to use them to make chemicals more cleanly, but factory conditions are hostile to biology, involving high heat, extreme acidity or alkalinity, and organic solvents.
- Fields
Chemistry
Microbiology & Immunology
Materials Science
- Topics
directed evolution
enzyme engineering
bacterial spores
- Grants
- 3 known grants, through Apr 2029
What they work on
- Build a high-throughput screen for enzyme activity using fluorescence-activated cell sorting, an instrument that sorts single particles by brightness, together with engineered chemical probes that fluoresce only when the displayed enzyme turns over its substrate.
- Generate a library of randomly mutated enzymes displayed on the surface of Bacillus subtilis spores, then select and characterize variants that stay active under high temperature, extreme pH, and organic solvents resembling chemical-plant conditions.
- Determine which mutations confer resistance in harsh environments while the enzyme is immobilized, aiming to extract design rules transferable to other industrially relevant enzymes.
- Compare chemical motifs for forming a well-defined molecular interface between engineered polymer scaffolds and the B. subtilis spore coat using dynamic covalent bonds that can form and reform.
- Engineer B. subtilis spores for catalytic bioremediation and combine them with synthetic polymers into living composite materials, then measure the materials' physical properties, dry-storage stability, recyclability, and catalytic performance across substrates.
- Develop a printing platform that arranges synthetic consortia of bacteria within defined polymers, so spacing and geometry can be varied to test how three-dimensional confinement alters cell phenotype, differentiation, communication, gene expression, and metabolism.
More about the research
A second obstacle is that enzymes usually need to be anchored to a solid support so they can be reused, and anchoring often degrades their performance. Work in this lab approaches both problems using bacterial spores, the dormant, seed-like form that some bacteria adopt to survive hard times. Spores tolerate harsh conditions, can be engineered to display enzymes on their outer surface, and still carry the genetic instructions needed to regrow, which makes them a natural bridge between living cells and durable materials. Across its projects the lab builds enzymes and materials on spore surfaces, combines spores with designed polymers, and asks how microbes behave when arranged in three-dimensional space rather than swirled in liquid culture.
Why it matters
Enzymes that keep working in hot, acidic, or solvent-rich conditions could make industrial chemical manufacturing cleaner and cheaper, and the mutations identified may yield design rules usable for many enzymes. Spore-polymer composites are aimed at degrading toxic environmental contaminants in a form that can be stored dry and reused. Understanding how spatially organized microbial communities behave could help in controlling or treating clinically relevant biofilms and in building biomaterials for human health.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Directed evolution of immobilized enzymes on bacterial spores
NSF · May 2026 – Apr 2029
Spatially Structured Synthetic Consortia of Microbes to Understand and Engineer Cells in 3D Environments
NIH · Aug 2023 – Jul 2028
CAREER: Catalytic Living Materials Constructed with Engineered Spores and Polymer Scaffolds
NSF · Jun 2023 – May 2028
Closest labs
Jeffrey Tabor
Rice University, TX·Microbiology & Immunology
Test how two Bacillus subtilis stress-response gene networks decode time-varying activity of their main transcription factors, using an optogenetic system to deliver constant or oscillatory light inputs.
Jack Gilbert
University of California-San Diego, CA·Microbiology & Immunology
Engineer Bacillus subtilis strains through genetic manipulation to survive long-term inside porous building materials while retaining the ability to competitively exclude multi-drug resistant organisms from surfaces.
Jay Lennon
Indiana University, IN·Microbiology & Immunology
Test competing models of how phage genomes become entrapped in Bacillus subtilis spores, using CRISPR editing of viral auxiliary sporulation genes and single-cell assays to assess suppression of the lytic cycle and chromosome segregation.
The school
University of California-Irvine: 46 labs on PI Pages, $645M a year on research, 524 research doctorates a year.
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