[Seminar] Biochemical Characterization of Microbial and Plant Cellulose Synthesis

Seminar

Title: Biochemical Characterization of Microbial and Plant Cellulose Synthesis

Speaker: Ming Tien

Affiliation: Penn State University

Host: Catarina Paquete, Inorganic Biochemistry and NMR Lab

Abstract:

Cellulose is a polymer of glucose linked by β-1,4 bonds. It is the most abundant renewable polymer on Earth. It is the major component of the plant cell wall. Interest in cellulose synthesis has intensified in recent years, mainly due to interest in the conversion of cellulose into bioethanol. Cellulose is not only synthesized by higher plants; microbes also synthesis cellulose. In both systems, cellulose is synthesized by membrane-bound glycosyltransferases, utilizing UDP-glucose to form the β-1,4-glucan polymer. The individual cellulose strands can then coalesce to form crystalline cellulose. The crystallinity is due to inter- and intra-molecular hydrogen bonding, such that water cannot even penetrate the cellulose strands. In plants, the crystallinity of cellulose imparts tensile strength and rigidity to the cell wall. Our research involves both the microbial and the high plant systems. In the microbial system, we have purified the cellulose synthase from Gluconoacetobacter hansenii. This enzyme is part of a multienzyme system. Our work has allowed us to identify the essential catalytic core of this complex. Work in the plant system has resulted in our determination of the stoichiometry of this multienzyme complex. How the stoichiometry impacts cellulose structure will be discussed.