title: Enzymatic synthesis of poly-L-lactide and poly-L-lactide-co-glycolide in an ionic liquid.
abstract: The syntheses of poly-L-lactide (PLLA) and poly-L-lactide-co-glycolide (PLLGA) is reported in the ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate [HMIM][PF(6)] mediated by the enzyme lipase B from Candida antarctica (Novozyme 435). The highest PLLA yield (63%) was attained at 90 degrees C with a molecular weight (M(n)) of 37.8 x 10(3) g/mol determined by size exclusion chromatography. This procedure produced relatively high crystalline polymers (up to 85% PLLA) as determined by DSC. In experiments at 90 degrees C product synthesis also occurred without biocatalyst, however, PLLA synthesis in [HMIM][PF(6)] at 65 degrees C followed only the enzymatic mechanism as ring opening was not observed without the enzyme. In addition, the enzymatic synthesis of PLLGA is first reported here using Novozyme 435 biocatalyst with up to 19% of lactyl units in the resulting copolymer as determined by NMR. Materials were also characterized by TGA, MALDI-TOF-MS, X-ray diffraction, polarimetry and rheology.
authors.affiliation: Departamento de Alimentos y Biotecnología, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico, DF, Mexico.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Chanfreau
authors.forename: Maria
authors.initials: M
authors.lastname: Mena
authors.forename: Jaime R
authors.initials: JR
authors.lastname: Porras-Domínguez
authors.forename: Mariana
authors.initials: M
authors.lastname: Ramírez-Gilly
authors.forename: Miquel
authors.initials: M
authors.lastname: Gimeno
authors.forename: Pedro
authors.initials: P
authors.lastname: Roquero
authors.forename: Alberto
authors.initials: A
authors.lastname: Tecante
authors.forename: Eduardo
authors.initials: E
authors.lastname: Bárzana
mesh_terms: D002175:Candida / Q000201:enzymology*; D002384:Catalysis; D004800:Enzymes, Immobilized; D005656:Fungal Proteins / Q000737:chemistry*; D007093:Imidazoles / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D019344:Lactic Acid / Q000138:chemical synthesis* / Q000737:chemistry; D008049:Lipase / Q000737:chemistry*; D011091:Polyesters / Q000138:chemical synthesis* / Q000737:chemistry; D011100:Polyglycolic Acid / Q000138:chemical synthesis* / Q000737:chemistry; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer
chemical_list: D004800:Enzymes, Immobilized; D005656:Fungal Proteins; D007093:Imidazoles; D007477:Ions; D011091:Polyesters; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; C033616:poly(lactide); C093667:Novozyme 435; D008049:Lipase