Poly immobilized lipase

Immobilized lipase Covalent binding on poly- Olive oil hydrolysis... 

Enzyme activity for the polymerization of lactones was improved by the immobilization on Celite [93]. Immobilized lipase PF adsorbed on a Celite showed much higher catalytic activity than that before the immobilization. The catalytic activity was further enhanced by the addition of a sugar or poly(ethylene glycol) in the immobilization. Surfactant-coated lipase efficiently polymerized the ring-opening polymerization of lactones in organic solvents [94]. 

Enzymatic resolution of racemic functionalized isoxazolines is a valuable technique for the preparation of enantio-merically enriched and pure 4,5-dihydroisoxazoles. These enzymatic resolutions exploit a variety of transformations of functional groups resident on the side-chains of the isoxazoline ring. The multipolymer enzymatic resolution of soluble polymer-supported alcohols 307 and 308 was achieved using an immobilized lipase from Candida antarctica (Novozym 435). The (R)-alcohol 309 was obtained in enantiomerically pure form (>99% ee) after its cleavage from the poly(ethylene glycol) (PEG) scaffold (Scheme 70) <2000JOG8527>. 

The enzymatic polymerization of methyl ricinoleate was performed using an immobilized lipase from Pseudomonas cepacia as catalyst. Reactions were conducted in bulk, with molecular sieves, at 80°C, for 7 days to give poly(ricinoleic acid) with Mw > 1 x 10s (Scheme 4.3) [32]. This result is generally uncharacteristic of other reports on related monomers given that lipase-catalyzed esterification of secondary hydroxyls proceeds slowly (see below) and ricinoleic acid purity to achieve such molecular weights must be very high. 

He, F., Wang, Y., Feng,)., Zhuo, R., and Wang, X. (2003) Synthesis of poly[(5 -benzyloxy-trimethylene carbonate) -co - (5,5 - di methyl-trimethylene carbonate)] catalyzed by immobilized lipase onsilica particles... 

Concentrated emulsions were also used to prepare substrates for the immobilization of enzymes and cells. Lipase was immobilized in hydrophobic porous polymers and the system employed in the hydrolysis of triacylglycerides [71]. Cells of Phanerochaete Chrysosporium were immobilized on porous poly(styrene-divinylbenzene) carrier and used for the degrading of 2-chloro-phenol [72]. The substrates were prepared as in Ref. 73. 

Lipases act in nature on oil-water interfaces and often have hydrophobic domains on their surface. Hence, immobilization by adsorption to a hydrophobic carrier is often a simple and effective way to immobilize Upases. A wide range of different hydrophobic support materials is commercially available, including synthetic acrylic, divinylbenzene-styrene or polypropylene polymers. An example of the latter is Accurel MP 1000, which is available from Membrana. Novozym 435 is immobilized on Lewatit VP OC 1600, a divinylbenzene-cross-linked poly(methyl methacrylate) resin produced by Lanxess (previously Bayer). 

Although there are notable exceptions as given below, the most common lipase-catalyst used for polyester synthesis is Candida antarctica lipase B (CALB) (please refer to Chapter 14 for more information on the structure and reaction mechanisms of CALB). The immobilized CALB catalyst that has been primarily used is Novozym 435, manufactured by Novozymes (Bagsvaerd, Denmark). Novozym 435 consists of CALB physically adsorbed within the macroporous resin Lewatit VPOC 1600 (poly[methyl methacrylate-co-butyl methacrylate], supplied by Bayer) (please refer to Chapter 3 for more information on Novozym 435). 

Apart from CALB other enzymes were shown to be able to successfully polymerize lactones. For instance Lipase PS-30, immobilized on Celite, was used as catalyst to study PDL-ROP under bulk reaction conditions. Poly(PDL) with M = 62000 and PDI 1.9 was reported [76]. Gross and coworkers could show that Humicola insolens cutinase (HiC) showed a high catalytic activity for enzymatic ROP of e-CL and PDL [87]. Poly(e-CL) with M n = 16000 (M /lVf = 3.1), in >99% yields was produced in bulk (70 °C, 24h) with 0.1% w/w immobilized HiC. Furthermore, using immobilized HiC in toluene (70 °C, 24h), PDL was converted to poly(PDL) (99% yield) with M = 44600 and Mw/M = 1.7. 

Furthermore, the ring-opening co-polymerization of BTMC with 5,5-dimethyl-trimethylene carbonate (DTC) by immobilized porcine pancreatic lipase (0.1 wt%) catalyzed in bulk copolymerization at 150°C for 24h [117]. Under these conditions, the highest molecular weight of poly(BTMC-co-DTC) of M =26 400 was obtained, with 83% monomer conversion. 

Lipase Immobilization on Ultrafine Poly(acrylic acid)-PoIy(vinyl alcohol) Hydrogel Fibers... 

Enzymatic, surface-initiated polymerizations of aliphatic polyesters was reported for wider clinical use of aliphatic polyesters 84). The hydroxyl terminated SAM acted as an initiation site for lipase B catalyzed ROP of aliphatic polyesters, such as poly(e-caprolactone) and poly (p-dioxanone) (Scheme 3). Another example of enzymatic SIP is the polymerization of poly (3-hydroxybutyrate) (PHB), where PHB synthase, fused with a His-tag at the N-terminus, was immobilized onto solid substrates through transition-metal complexes, Ni (II)-NTA, and the immobilized PHB synthase catalyzed the polymerization of 3-R-hydroxybutyry 1-coenzyme A (3HB-CoA) to PHB 85). 

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