Professor
Sung Ok Han
Department of Biotechnology, Institute of Life Science and Natural Resources, Korea University, Seoul 02841, Republic of Korea
Title: Renewable Porphyrin Biosynthesis and Its Electrical and Photoactive Applications Enabled by Engineered Corynebacterium glutamicum
Byeong-Hyeon Cho1, Myeong-Eun Lee 1,2, Young Jin Ko3, Sung Ok Han 1,2,*
1 Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
2 Institute of Life Science and Natural Resources, Korea University, Seoul 02841, Korea
3 Department of Biotechnology, College of Applied Life Science (SARI), Jeju National University, Jeju 63243, Republic of Korea
* Email of the corresponding authors: Sung Ok Han (samhan@korea.ac.kr)
Porphyrins are tetrapyrrole molecules composed of four pyrrole units connected by methine bridges, and they play essential roles in biological functions such as oxygen transport, photosynthesis, and catalysis. Corynebacterium glutamicum strains designated as GRAS were engineered to enhance their porphyrin biosynthetic pathway, and increasing the aminolevulinic acid (ALA) precursor supply together with downstream pathway optimization, cofactor supplementation, and membrane engineering markedly improved the production of various porphyrin derivatives. Due to their rich π-electron system and strong metal-chelating properties, metalloporphyrins such as Fe- and Zn-porphyrins exhibit electrical conductivity, UV–visible light absorption, and antimicrobial activity. Fe-porphyrins (heme) were polymerized by an enzyme complex composed of heme polymerases, achieving a 1.5-fold increase in efficiency. The resulting polymer, hemozoin, exhibited 3.0-fold higher electrical conductivity compared to monomeric heme, making it suitable for potential use as a conductive biopolymer. Zn-porphyrins, on the other hand, showed up to 6.1-fold stronger photoprotective performance, and when combined with lignin derived from lignocellulosic biomass, the bio-based Zn-porphyrin sunscreen achieved broad-spectrum UV shielding, high SPF values, and notable radical-scavenging ability. Zn-porphyrins also exhibited antibacterial activity driven by photoinduced reactive oxygen species (ROS) generation. Immobilization of Zn-porphyrins onto a cellulose membrane yielded a versatile antibacterial membrane, achieving over 90% antibacterial efficiency under light irradiation, demonstrating its potential for industrial applications. Overall, metabolic engineering of the porphyrin biosynthetic pathway in C. glutamicum and the microbial production of metalloporphyrins present a promising, renewable, and high-value-added strategy for diverse industrial uses.
Biography of the presenting author
Professor Sung Ok Han joined Korea University’s Department of Biotechnology in 2007, bringing 16 years of extensive international professional experience. He earned his Master’s and Ph.D. in Department of Microbiology, the University of Sydney. Dr. Han significantly deepened his expertise through postdoctoral research in anaerobic microbiology and molecular biology at the University of Oklahoma and the University of California, Davis. Before returning to academia, he served as a Senior Staff Scientist at RITE (2005-2007), gaining practical bioengineering experience in enzymology, gene regulation, and the production of amino acids and biochemicals. Since 2007, Professor Han has focused his research at Korea University on converting renewable bioresources into valuable chemicals, biomaterials, and functional foods. As a microbial bioengineer, he leverages knowledge-based bioengineering and synthetic biology to tailor microbial systems for diverse applications. His substantial contributions to metabolic and enzyme engineering are highlighted by his publication of over 200 papers in SCI journals.
Presenting author details
Full name: Sung Ok Han
Contact number: +82-2-3290-3151
Email: samhan@korea.ac.kr
LinkedIn:
Session name/ number:
Category: Oral presentation