title: Polymerization of propyl malolactonate in the presence of Candida rugosa lipase.
abstract: To gain better insight into mechanistic features of enzyme-catalyzed malolactonate polymerization, reactions with propyl malolactonate were analyzed while varying enzyme concentration, reaction media composition, and reaction temperature. Monomer conversion and product molecular weights were characterized by (1)H NMR and MALDI-TOF MS, respectively. A high extent of thermal polymerization of propyl malolactonate was observed, while the polymer chain length in all reactions was controlled by the elimination of alpha-hydrogen from propyl malolactonate with formation of a new initiator and the new chains. The most efficient enzymatic catalysis occurred in toluene (2.11 M monomer) at 60 degrees C. Candida rugosa lipase (10 wt %) accelerated polymerization 25-fold over the rate of thermal polymerization. The maximum poly(propyl malate) number-average molecular weight obtained was 5000 Da at 20 wt % enzyme with a polydispersity of 1.15. These values compare with 1800 Da and 1.5, respectively, in the absence of enzyme.
authors.affiliation: Department of Chemical and Biological Engineering, Department of Chemistry, and Bioengineering Center, Tufts University, 4 Colby Street, Medford, Massachusetts 02155, USA.
authors.forename: Anna A
authors.initials: AA
authors.lastname: Panova
authors.forename: Sonia
authors.initials: S
authors.lastname: Taktak
authors.forename: Solo
authors.initials: S
authors.lastname: Randriamahefa
authors.forename: Sandrine
authors.initials: S
authors.lastname: Cammas-Marion
authors.forename: Philippe
authors.initials: P
authors.lastname: Guerin
authors.forename: David L
authors.initials: DL
authors.lastname: Kaplan
mesh_terms: D002175:Candida / Q000201:enzymology*; D002384:Catalysis; D007202:Indicators and Reagents; D007700:Kinetics; D007783:Lactones / Q000737:chemistry* / Q000302:isolation & purification; D008049:Lipase / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008970:Molecular Weight; D011091:Polyesters / Q000138:chemical synthesis* / Q000737:chemistry; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013816:Thermodynamics
chemical_list: D007202:Indicators and Reagents; D007783:Lactones; D011091:Polyesters; D011108:Polymers; D008049:Lipase