Seiichi Taguchi
Tokyo University of Agriculture, Japan
Biography
Abstract
In our previous study, the first incorporation of lactate (D-LA) into the P(3HB) backbone in the Escherichia coli-based microbial factory carrying a newly developed D-LA-polymerizing enzyme LPE was reported [1,2]. LPE was one of the artificially evolved PHA synthases through our long-term enzyme engineering studies [3,4]. In the second generation, LPE has led us to further expand the range of structural diversity of PHA members other than LA-based polymers. New unnatural monomeric constituents such as glycolic acid and 2-hydroxybutyrate can also be polymerized by LPE. Like these, the study intends to synthesize the chiral copolymers with various monomer compositions, owing to the extremely high enantio-selectivity and broad substrate specificity of LPE catalyst [5]. In this conference, the main focus will be on the overview of biosynthesis and properties of LPE-catalyzed polymers. The possibility of “secretion” of polymerized ester-products by microbial platform should be a promising issue to overcome the cell volume limitation in the large amount of production of microbial polymers. Fortunately, we have met the “secretion” of low-molecular-weight D-LA-based polymers [or D-LA-based oligomers (D-LAOs)] [6)] The second topic will be about the first observation of microbial secretion of D-LAOs and its advanced microbial secretion platform through the chain transfer reaction and modified cultivation conditions. Furthermore, synthesis of lactate (LA)-based poly(ester-urethane) using hydroxyl-terminated LA-based oligomers from a microbial secretion system will be presented.