Mechanistic limitations in the synthesis of polyesters by lipase‐catalyzed ring‐opening polymerization

Panova, Anna A.; Kaplan, David L.

doi:10.1002/bit.10754

Cited by 35 publications

(34 citation statements)

References 34 publications

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“…In general, this is not a limitation of the reaction because CALB catalyzed polymerizations of lactones are well-known from the literature so that enough water seems to be available even with dried enzyme preparations. 15,31,32 In the synthesis of poly(β-alanine) from β-lactam (1) reported by Schwab et al, 18 the authors could also show that in contrast to pathway B of Scheme 1, β-alanine (3) is not a substrate for the lipase catalyzed synthesis of poly(β-alanine), a surprising result that was confirmed in a variety of different solvents to rule out a solvent dependency. 29 This result is in agreement with the findings of Hollmann et al 25 who observed an inactivation of CALB by acids exhibiting a pK a below 4.8.…”

Section: ' Results and Discussionmentioning

confidence: 89%

Atomistic Model for the Polyamide Formation from β-Lactam Catalyzed by Candida antarctica Lipase B

et al. 2011

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Lipases have emerged from their metabolic use in ester cleavage of triglycerides to versatile biocatalysts that can be used for enantioselective hydrolysis of esters in water and for transesterification and transformation of esters to amides in organic solvents. 1 In addition, during the last 10 years, enzymes have also proven to be effective catalysts for polymerization reactions that proceed cost effectively with high regio-, enantio-, and chemoselectivity under relatively mild conditions. 2,3 In this respect, Candida antarctica lipase B (CALB) immobilized on polyacrylic resin (Novozyme 435) is a particularly useful enzyme preparation because it shows exceptionally high stability and good activity in organic solvents, even at higher temperatures. Although CALB has successfully been employed for the synthesis of polyesters from linear 4-8 and cyclic 9-15 starting materials, little has been reported on the preparation of polyamides catalyzed by enzymes. 16,17 Schwab et al. have recently described the first approach for a synthesis of unbranched poly(β-alanine), nylon 3, by enzymatic ring-opening polymerization starting from unsubstituted β-lactam (2-azetidinone, β-propiolactam). 18 The polymerization, however, proceeds with poor yield and with a maximum chain length of only 18 units and an average length of 8. Therefore, an optimization of the process is still necessary to produce a polymer for industrial use. This is, indeed, desirable because it

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Section: ' Results and Discussionmentioning

confidence: 89%

Atomistic Model for the Polyamide Formation from β-Lactam Catalyzed by Candida antarctica Lipase B

et al. 2011

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“…However, mechanistic limitations exist in such reactions, and these include the limit for methoxy-poly(ethylene glycol) initiator esterification and slower monomer conversion in concentrated solutions, factors that have been investigated by researchers (Panova and Kaplan 2003). Ultrasonic irradiation has been shown to greatly improve C. antarctica lipase B-mediated ROP of e-CL to poly-6-hydroxyhexanoate in the ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate.…”

Section: Lipase-catalyzed Biopolymer Synthesis and Degradationmentioning

confidence: 99%

An insight into microbial lipases and their environmental facet

Kanmani¹,

Aravind²,

Kumaresan³

2014

Int. J. Environ. Sci. Technol.

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Lipases are serine hydrolases that catalyze the hydrolysis and synthesis of esters formed from glycerol and long-chain fatty acids, by acting at the oil-water interface. Lipases from microbial sources have received heightened attention for an array of industrial applications, and these enzymes have been well exploited in the environmental sector as well. In this article, we present an overview of microbial lipase, including the microorganisms from which it could be produced; the application of recombinant DNA technology tools to produce lipase with enhanced properties, the effective use of waste materials as substrates for lipase production; the usage of statistical tools to efficiently optimize the production medium; lipase purification strategies; and the immobilization of the enzyme on a variety of support materials. The next section of the article provides a gist of its application in diversified spheres and focusses exclusively on the environmentally relevant ones. Lipasecatalyzed esterification, transesterification, and interesterification reactions, an emerging area of green chemistry; lipase-mediated in vitro biopolymer synthesis and degradation; and the application of lipase for remediating fat and oil constituents in wastewater are dealt with in-depth. When its full potential is harnessed, the enzyme could play a pivotal role in environmental management.

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“…The scaled‐up reaction in toluene (45 °C for 24 h) increased the PCL molecular weight ( M n ) to ∼41 500 g mol ‐1 with 78% isolated yield and 1.69 PDI. Panova and Kaplan examined the effect of different ϵ‐caprolactone concentrations (0.065–7.8 mol L ‐1 ) on the Novozym 435‐catalyzed ROP in toluene at 70 °C, and suggested that both the monomer conversion and the degree of polymerization increased with monomer concentration (up to certain concentrations) and then decreased with further increase in the monomer concentration. The decreased monomer conversion in concentrated monomer solutions is probably due to the poorer partitioning of PCL between toluene and the lipase, which could lead to enzyme inhibition by the reaction product and/or slow diffusion of monomer to the enzyme active site.…”

Section: Enzymatic Rop In Organic Solventsmentioning

confidence: 99%

Enzymatic ring‐opening polymerization (ROP) of polylactones: roles of non‐aqueous solvents

Zhao

2017

J of Chemical Tech & Biotech

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Aliphatic polyesters such as polylactides (PLAs) and other polylactones are thermoplastic, biodegradable and biocompatible polymers with the potential to replace petro-chemical-based synthetic polymers. A benign route for synthesizing these polyesters is through the enzyme-catalyzed ring-opening polymerization (ROP) reaction; this type of enzymatic process is very sensitive to reaction conditions such as solvents, water content and temperature. This review systematically evaluates the crucial roles of different solvents (such as solvent-free/in bulk, organic solvents, supercritical fluids, ionic liquids, and aqueous biphasic systems) on the degree of polymerization and polydispersity. In general, many studies suggest that hydrophobic organic solvents with minimum water contents lead to efficient enzymatic polymerization and subsequently high molecular weights of polyesters; the selection of solvents is also limited by the reaction temperature, e.g. the ROP of lactide is often conducted at above 100 ∘ C, therefore, the solvent typically needs to have its boiling point above this temperature. The use of supercritical fluids could be limited by its scaling-up potential, while ionic liquids have exhibited many advantages including their low-volatility, high thermal stability, controllable enzyme-compatibility, and a wide range of choices. However, the fundamental and mechanistic understanding of the specific roles of ionic liquids in enzymatic ROP reactions is still lacking. Furthermore, the lipase specificity towards L-and D-lactide is also surveyed, followed by the discussion of engineered lipases with improved enantioselectivity and thermal stability. In addition, the preparation of polyester-derived materials such as polyester-grafted cellulose by the enzymatic ROP method is briefly reviewed.

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Mechanistic limitations in the synthesis of polyesters by lipase‐catalyzed ring‐opening polymerization

Cited by 35 publications

References 34 publications

Atomistic Model for the Polyamide Formation from β-Lactam Catalyzed by Candida antarctica Lipase B

Atomistic Model for the Polyamide Formation from β-Lactam Catalyzed by Candida antarctica Lipase B

An insight into microbial lipases and their environmental facet

Enzymatic ring‐opening polymerization (ROP) of polylactones: roles of non‐aqueous solvents

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