• 2015 ~ present, Associate Professor, North Carolina State University
• 2011 ~ present, Adjunct Professor, Seoul National University
• 2016 Visiting Professor, KAIST
• 2009 ~ 2015, Assistant Professor, North Carolina State University
• 2007 ~ 2008, Postdoctoral Researcher, Bioenergy, National Renewable Energy Laboratory
• 2006 ~ 2007, Postdoctoral Researcher, Bioenergy, University of Tennessee at Knoxville
• 2006, Ph.D., Pulp and Paper, North Carolina State University
• 2001, M.S., Pulp and Paper, Seoul National University, Korea
• 1997, B.S., Forest Products, Seoul National University, Korea

Teaching

• PSE 355 Pulp and Paper Unit Processes I
• PSE 425 Bioenergy and Biomaterials Engineering
• WPS 760 Engineering Unit Operations for Biomass Conversion

Research Interests

His research is focused on the fundamental understanding of lignocellulosic biomass reactivity (changes in biomass chemistry/structure and their effects on conversion process) for both biochemical and thermochemical conversion processes into biofuels.

• Thermal pretreatment and its effect on fast pyrolysis. Thermal pretreatment of biomass such as torrefaction has a potential to be integrated with fast pyrolysis and gasification operation. His research is focused on the characterization of biomass chemistry/structure changes during thermal pretreatment and the evaluation of bio-oil quality when torrefied biomass is used.
• Cellulose crystalline structure and its allomorphs. Fundamental understanding of cellulose crystalline structure is critical for many applications such as paper, textiles, chemicals, and bioenergy. Recently we have applied new technology (sum-frequency-generation vibration spectroscopy) together with x-ray diffraction and solid-state NMR to elucidate its structure. SFG spectroscopy can selectively detect cellulose crystalline structure without interference from hemicellulose and lignin.
• Biomass post-treatment and enzymatic hydrolysis. Inefficient enzymatic hydrolysis of biomass is largely due to the recalcitrant nature of lignocellulosic biomass. This study focuses on identifying the physico-chemical properties of biomass responsible for low conversion efficiency and developing post-treatment operations to overcome recalcitrant issues.

Publications

• Characterization of biofuel refinery byproduct via selective electrospray ionization tandem mass spectrometry (2017)
• Effect of the two-stage autohydrolysis of hardwood on the enzymatic saccharification and subsequent fermentation with an efficient xylose-utilizing saccharomyces cerevisiae (2016)
• Removal of furan and phenolic compounds from simulated biomass hydrolysates by batch adsorption and continuous fixed-bed column adsorption methods (2016)
• Biomass pretreatments capable of enabling lignin valorization in a biorefinery process (2016)
• Improving sugar yields and reducing enzyme loadings in the deacetylation and mechanical refining (DMR) process through multistage disk and szego refining and corresponding techno-economic analysis (2016)
• Use of mechanical refining to improve the production of low-cost sugars from lignocellulosic biomass (2016)
• Effects of delignification on crystalline cellulose in lignocellulose biomass characterized by vibrational sum frequency generation spectroscopy and x-ray diffraction (2015)
• Fast pyrolysis of lignin-coated radiata pine (2015)
• Progressive structural changes of Avicel, bleached softwood, and bacterial cellulose during enzymatic hydrolysis (2015)
• Thermal and storage stability of bio-oil from pyrolysis of torrefied wood (2015)

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