A microbial factory for lactate-based polyesters using a lactate-polymerizing enzyme.
Polylactate (PLA) is synthesized as a representative bio-based polyester by the chemo-bio process on the basis of metal catalyst-mediated chemical polymerization of lactate (LA) supplied by microbial fermentation. To establish the one-step microbial process for synthesis of LA-based polyesters, we explored whether polyhydroxyalkanoate (PHA) synthase would exhibit polymerizing activity toward a LA-coenzyme A (CoA), based on the fact that PHA monomeric constituents, especially 3-hydroxybutyrate (3HB), are structurally analogous to LA. An engineered PHA synthase was discovered as a candidate by a two-phase in vitro polymerization system previously developed. An LA-CoA producing Escherichia coli strain with a CoA transferase gene was constructed, and the generation of LA-CoA was demonstrated by capillary electrophoresis/MS analysis. Next, when the engineered PHA synthase gene was introduced into the resultant recombinant strain, we confirmed the one-step biosynthesis of the LA-incorporated copolyester, P(6 mol% LA-co-94 mol% 3HB), with a number-average molecular weight of 1.9 x 10(5), as revealed by gel permeation chromatography, gas chromatography/MS, and NMR.
Taguchi
Seiichi
S
Division of Biotechnology and Molecular Chemistry, Graduate School of Engineering, Hokkaido University, N13-W8, Kita-ku, Sapporo 060-8628, Japan. staguchi@eng.hokudai.ac.jp
Yamada
Miwa
M
Matsumoto
Ken'ichiro
K
Tajima
Kenji
K
Satoh
Yasuharu
Y
Munekata
Masanobu
M
Ohno
Katsuhiro
K
Kohda
Katsunori
K
Shimamura
Takashi
T
Kambe
Hiromi
H
Obata
Shusei
S
D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism*; D002849:Chromatography, Gas; D003065:Coenzyme A / Q000378:metabolism*; D019075:Electrophoresis, Capillary; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D019344:Lactic Acid / Q000096:biosynthesis*; D013058:Mass Spectrometry; D019906:Nuclear Magnetic Resonance, Biomolecular; D011091:Polyesters; D011108:Polymers; D015202:Protein Engineering
D011091:Polyesters; D011108:Polymers; D019344:Lactic Acid; C033616:poly(lactide); D000217:Acyltransferases; C077225:poly(3-hydroxyalkanoic acid) synthase; D003065:Coenzyme A