Lipase polymerization Candida

Enzyme-catalysed condensation polymerization of 11-hydroxyundecanoic add with lipase from Candida cylindracea. Polymer, 35 (16), 3576-3578. 

In this work we have shown that it is possible to use an ezyme to catalyze the polycondensatioh reaction to form polyamides. The large number of polyamides that have been made indicate diat lipases from Candida antarctica and Mucor miehei are rather nonspecific and can be used generally for polyamide synthesis. In a particular example, a water-soluble polyamide has been produced from dimethyl adipate and ethylene triamine via this enzyme-catalyzed reaction at 50-110°C. The enzymatic polymerization is easy to do and... 

Aliphatic polyesters were also synthesized via an enzymatic polymerization of dicarboxyiic acids and glycols in a solvent-free system [69, 70]. The lipase from Candida antarctica (lipase CA) provided an efficient catalysis of the polymerization under mild reaction conditions, despite the presence of a heterogeneous mixture of the monomers and catalyst. The ahphatic chain length of the monomers had a major effect on both the polymer yield and molecular weight typically, a molecular weight in excess of 1 x Da was obtained when the reaction was conducted under reduced pressure. However, the addition of a small amount of adjuvant proved effective for polymer production when both monomers were solid at the reaction temperature [71]. 

Various cychc esters have been subjected to hpase-catalyzed ring-opening polymerization (ROP), notably of four- to 17-membered nonsubstituted lactones. Initially, it was shown that medium-sized lactones, 5-valerolactone (5-VL, six-membered) and e-CL (seven-membered), were each polymerized via the action of a lipase from Candida cylindracea (hpase CC), hpases BC and PF, and a porcine pancreatic hpase (PPL) [83,84]. Later, a variety of cychc esters with different ring sizes and structures were also polymerized via a hpase-mediated catalysis. 

Substituted acrylic monomers. The reactants (methyl acrylate plus alcohol or amine) were added neat or in a non-aqueous solvent together with Novozym 435 immobilized lipase from Candida antarctica as a catalyst. Molecular sieves (4A) were used to remove water in order to shift the reaction equilibrium to product formation, and also to eliminate side reactions due to Michael addition that was usually enhanced by the presence of water or methanol. Unreacted starting materials were removed by evaporation, and the monomer products obtained without further purification. TLC analysis indicated that the desired products had formed. The purity of the products was confirmed by NMR and IR analysis. The two monomers were successfully polymerized in a separate step. 

M. Monier, Y. Wei, and A. Sarhan, Evaluation of the potential of polymeric carriers based on photo-crosshnkable chitosan in the formulation of lipase from Candida rugosa immobilization, Journal of Molecular Catalysis B Enzymatic, 63 (1), 93-101, 2010. 

Table 2 Polymerization of lactones with PhaZA/a and lipase from Candida cylindracea (CC)...

In this case study, an enzymatic hydrolysis reaction, the racemic ibuprofen ester, i.e. (R)-and (S)-ibuprofen esters in equimolar mixture, undergoes a kinetic resolution in a biphasic enzymatic membrane reactor (EMR). In kinetic resolution, the two enantiomers react at different rates lipase originated from Candida rugosa shows a greater stereopreference towards the (S)-enantiomer. The membrane module consisted of multiple bundles of polymeric hydrophilic hollow fibre. The membrane separated the two immiscible phases, i.e. organic in the shell side and aqueous in the lumen. Racemic substrate in the organic phase reacted with immobilised enzyme on the membrane where the hydrolysis reaction took place, and the product (S)-ibuprofen acid was extracted into the aqueous phase. 

In polyester synthesis via ring-opening polymerizations, metal catalysts are often used. For medical applications of polyesters, however, there has been concern about harmful effects of the metallic residues. Enzymatic synthesis of a metal-free polyester was demonstrated by the polymerization of l,4-dioxan-2-one using Candida antarctica lipase (lipase CA). Under appropriate reaction conditions, the high molecular weight polymer (molecular weight = 4.1 x 10" ) was obtained. 

Since then, the process has been extended to a wide variety of lactones of different size and to several lipases, as recently reviewed [93-96]. Interestingly, large-membered lactones, which are very difficult to polymerize by usual anionic and coordination polymerizations due to the low ring strain, are successfully polymerized by enzymes. Among the different lipases available, that fi om Candida antarctica (lipase CA, CALB or Novozym 435) is the most widely used due to its high activity. An alcohol can purposely be added to the reaction medium to initiate the polymerization instead of water. The polymerization can be carried out in bulk, in organic solvents, in water, and in ionic liquids. Interestingly, Kobayashi and coworkers reported in 2001 the ROP of lactones by lipase CA in supercritical CO2... 

Chemoenzymatic polymerizations have the potential to further increase macro-molecular complexity by overcoming these limitations. Their combination with other polymerization techniques can give access to such structures. Depending on the mutual compatibility, multistep reactions as well as cascade reactions have been reported for the synthesis of polymer architectures and will be reviewed in the first part of this article. A unique feature of enzymes is their selectivity, such as regio-, chemo-, and in particular enantioselectivity. This offers oppormnities to synthesize novel chiral polymers and polymer architectures when combined with chemical catalysis. This will be discussed in the second part of this article. Generally, we will focus on the developments of the last 5-8 years. Unless otherwise noted, the term enzyme or lipase in this chapter refers to Candida antarctica Lipase B (CALB) or Novozym 435 (CALB immobilized on macroporous resin). 

Other authors have described the lipase-catalyzed chemoselective acylation of alcohols in the presence of phenolic moities [14], the protease-catalyzed acylation of the 17-amino moiety of an estradiol derivative [15], the chemoselectivity in the aminolysis reaction of methyl acrylate (amide formation vs the favored Michael addition) catalyzed by Candida antarctica lipase (Novozym 435) [16], and the lipase preference for the O-esterification in the presence of thiol moieties, as, for instance, in 2-mercaptoethanol and dithiotreitol [17]. This last finding was recently exploited for the synthesis of thiol end-functionalized polyesters by enzymatic polymerization of e-caprolactone initiated by 2-mercaptoethanol (Figure 6.2)... 

Adsorption of enzymes to various polymeric resins is a straightforward means for immobilization. Zwitterionic molecules such as proteins can bind to both anionic and cationic ion exchange resins. Hydrophobic macroporous resins are also useful for immobilizing many enzymes, particularly lipases. For example, an immobilized form of Candida antarctica lipase B (CAL-B) on acrylic resin has been sold for many years under the name, Novozym 435 (N435). The enzyme is produced in a modified Aspergillus organism by submerged fermentation and is subsequently adsorbed onto a macroporous... 

Five-membered unsubstituted lactone, y-butyro-lactone (y-BL), is not polymerized by conventional chemical catalysts. However, oligomer formation from y-BL was observed by using PPL or Pseudomonas sp. lipase as catalyst.1523 157 d-Valerolactone (<3-VL, six-membered) was polymerized by various lipases of different origin to give the polymer with Mn of several thousands.148 Another six-membered lactone, l,4-dioxan-2-one, was polymerized by Candida antarctica lipase (lipase CA) to give the polymer with Mw higher than 4 x 104.158 The resulting polymer is expected as a metal-free polymeric material for medical applications. 

Nakaoki, T., Kalra, B., Kumar, A., Gross, R.A., Kirk, O., and Christensen, M. (2002) Candida antarctica lipase B catalyzed polymerization of lactones Effect of immobilization matrix on polymerization kinetics and molecular weight. Abstracts of Papers of the Am. Chem. Soc., 224, U473. 

---