Microbial Production of Lactate-Enriched Poly[(R)-lactate-co-(R)-3-hydroxybutyrate] with Novel Thermal Properties

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• 作者：Miwa Yamada ; Ken’ ; ichiro Matsumoto ; Takanori Nakai ; Seiichi Taguchi*
• 刊名：Biomacromolecules
• 出版年：2009
• 出版时间：April 13, 2009
• 年：2009
• 卷：10
• 期：4
• 页码：677-681
• 全文大小：209K
• 年卷期：v.10,no.4(April 13, 2009)
• ISSN：1526-4602

文摘

Considerable enrichment of the lactate (LA) fraction in Poly[(R)-LA-co-(R)-3-hydroxybutyrate (3HB)] has been achieved, reaching up to 47 mol % from the previous 6 mol % [S. Taguchi et al. Proc. Natl. Acad. Sci. U.S.A. 2008, 105 (45), 17323−17327], when recombinant Escherichia coli W3110, harboring the LA-polymerizing enzyme gene together with three genes for supplying monomers, lactyl-coenzyme A (CoA), and 3-hydroxybutyryl-CoA, were grown on glucose under anaerobic conditions. The molecular weights of the copolymer were M_n = 1.5 × 10⁴ g/mol and M_w = 2.0 × 10⁴ g/mol, respectively. Notably, alkaline-hydrolyzed product analysis revealed that only the (R)-enantiomer of LA was incorporated in the copolymer. Furthermore, the triad sequence of LA-LA-LA was clearly detected in the polymer chain based on NMR analysis. A remarkably contrasting melting temperature was observed between the copolymer obtained here P[(R)-LA-co-(R)-3HB] (157 °C) and the chemically synthesized P[(S)-LA-co-(R)-3HB] (105 °C) with similar monomer composition.