Sang-Jin Kim

Research Assistant Professor

Brandizzi Lab member
sjkim@msu.edu

Research: Improving Plants by Manipulating the Plant Cell Wall

As a researcher in Great Lakes Bioenergy Research Center (GLBRC), and part of Dr. Federica Brandizzi's laboratory, Dr. Kim has been conducting basic research that generates technology to convert cellulosic biomass into ethanol and other advanced biofuels. Developing plants with traits that increase the value of the crop as a biofuel feedstock by manipulating plant cell wall is one path to achieving that goal.

The plant cell wall consists of cellulose, hemicellulose, pectin and lignin. The components of the plant cell wall each play an important role during plant growth by modulating cell expansion and providing mechanical support and barriers.

Bright field image of cross section of flax stem. Phloem fibers of flax (Linum usitatissimum) are rich in thick cell walls unlike the thin walls of xylem that are composed mostly of lignin. The thick cell walls of phloem fibers consist of
cellulose and hemicelluloses. Hemicelluloses are synthesized at the Golgi and are then secreted to the cell wall.
*By Starla Zemelis-Durfee, Brandizzi lab.*

Dr. Kim has studied hemicellulose, which is comprised of a variety of sugars. Certain types of polysaccharides, such as mixed-linkage glucan (MLG), are easier to convert to ethanol than others due to their simple composition and digestibility. Research has looked into how MLG is made and transported within biofuel crops like sorghum, with the goal of increasing the overall amount of MLG output, without incurring agronomic penalties.

Besides MLG, pectin is also one of the important cell wall components essential for plant growth and development. By generating plants overexpressing or lacking specific genes in pectin synthesis and modification, our group has demonstrated that manipulating pectin could impact plant growth and cell wall properties that can favorably affect plant quality and quantity as a biofuel feedstock.