Microbial monomers custom-synthesized to build true bio-derived aromatic polymers

• Published in: Applied microbiology and biotechnology Vol. 97; no. 20; pp. 8887 - 8894
• Main Authors: Fujita, Tomoya, Nguyen, Hieu Duc, Ito, Takashi, Zhou, Shengmin, Osada, Lisa, Tateyama, Seiji, Kaneko, Tatsuo, Takaya, Naoki
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.10.2013; Springer; Springer Nature B.V
• Subjects: Amino acids; Bacteria; Biomass; Biomedical and Life Sciences; Bioplastics; Biopolymers; Biopolymers - biosynthesis; Bioreactors - microbiology; Biotechnological Products and Process Engineering; Biotechnology; Carbon dioxide fixation; Cellulose; Chemicals; Cloning; Dehydrogenases; Derivatives; Design; Dextrose; E coli; Encoding; Enzymes; Escherichia coli; Escherichia coli - genetics; Escherichia coli - metabolism; Fermentation; Genetic Engineering; Glucose; Glucose metabolism; Lactates - metabolism; Life Sciences; Metabolism; Metabolites; Microbial Genetics and Genomics; Microbiology; Microorganisms; Monomers; Phenylalanine; Plasmids; Polymerase chain reaction; Polymers; Renewable resources; Science; Studies; Trace elements; Ultraviolet radiation; Volatile Organic Compounds - metabolism; Japan; Shikimate pathway; Phenyllactic acid; Plastics; Phenylpyruvate reductase; Plant biomass; Phenylpropanoid
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-013-5078-4

Aromatic polymers include novel and extant functional materials although none has been produced from biotic building blocks derived from primary biomass glucose. Here we screened microbial aromatic metabolites, engineered bacterial metabolism and fermented the aromatic lactic acid derivative β-phenyllactic acid (PhLA). We expressed the Wickerhamia fluorescens gene ( pprA ) encoding a phenylpyruvate reductase in Escherichia coli strains producing high levels of phenylalanine, and fermented optically pure (>99.9 %) D -PhLA. Replacing pprA with bacterial ldhA encoding lactate dehydrogenase generated L -PhLA, indicating that the produced enzymes converted phenylpyruvate, which is an intermediate of phenylalanine synthesis, to these chiral PhLAs. Glucose was converted under optimized fermentation conditions to yield 29 g/l d -PhLA, which was purified from fermentation broth. The product satisfied the laboratory-scale chemical synthesis of poly( d -PhLA) with M w 28,000 and allowed initial physiochemical characterization. Poly( d -PhLA) absorbed near ultraviolet light, and has the same potential as all other biomass-derived aromatic bioplastics of phenylated derivatives of poly(lactic acid). This approach to screening and fermenting aromatic monomers from glucose exploits a new era of bio-based aromatic polymer design and will contribute to petroleum conservation and carbon dioxide fixation.