AUTHOR=Arai Shuzo , Sakakibara Sayaka , Mareschal Robin , Ooi Toshihiko , Zinn Manfred , Matsumoto Ken’ichiro 

TITLE=Biosynthesis of Random-Homo Block Copolymer Poly[Glycolate-ran-3-Hydroxybutyrate (3HB)]-b-Poly(3HB) Using Sequence-Regulating Chimeric Polyhydroxyalkanoate Synthase in Escherichia coli

JOURNAL=Frontiers in Bioengineering and Biotechnology

VOLUME=8

YEAR=2020

URL=https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2020.612991

DOI=10.3389/fbioe.2020.612991

ISSN=2296-4185

ABSTRACT=<p>Glycolate (GL)-containing polyhydroxyalkanoate (PHA) was synthesized in <italic>Escherichia coli</italic> expressing the engineered chimeric PHA synthase PhaC<sub><italic>AR</italic></sub> and coenzyme A transferase. The cells produced poly[GL-<italic>co</italic>-3-hydroxybutyrate (3HB)] with the supplementation of GL and 3HB, thus demonstrating that PhaC<sub><italic>AR</italic></sub> is the first known class I PHA synthase that is capable of incorporating GL units. The triad sequence analysis using <sup>1</sup>H nuclear magnetic resonance indicated that the obtained polymer was composed of two distinct regions, a P(GL-<italic>ran</italic>-3HB) random segment and P(3HB) homopolymer segment. The random segment was estimated to contain a 71 mol% GL molar ratio, which was much greater than the value (15 mol%) previously achieved by using PhaC1<sub><italic>P</italic></sub><sub><italic>s</italic></sub>STQK. Differential scanning calorimetry analysis of the polymer films supported the presence of random copolymer and homopolymer phases. The solvent fractionation of the polymer indicated the presence of a covalent linkage between these segments. Therefore, it was concluded that PhaC<sub><italic>AR</italic></sub> synthesized a novel random-homo block copolymer, P(GL-<italic>ran</italic>-3HB)-<italic>b</italic>-P(3HB).</p>