Synthesis of alkyl (R)-lactates and alkyl (S,S)-O-lactyllactates by alcoholysis of rac-lactide using Novozym 435

Ko, Sung-Jin; Won, Keehoon; Kang, Han‐Young; Kim, Bum Tae; Lee, Yeon Soo; Lee, Hyuk

doi:10.1016/j.tetlet.2006.07.034

Cited by 22 publications

(7 citation statements)

References 11 publications

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“…A strategy to separate enantiomeric l ‐ and d ‐lactide through an enzymatic kinetic resolution was also proposed. Such a strategy was first reported by Jeon et al., who performed an enantioselective enzymatic alcoholysis in a THF/hexane solvent system, which gave rise to enantiopurities of >97 % enantiomeric excess ( ee ) . Contacting both lactides with an alcohol and Candida antarctica lipase B (CALB) results initially in the generation of both l ‐ and d ‐alkyllactyllactates.…”

Section: Synthesis Of Lactidementioning

confidence: 99%

Lactide Synthesis and Chirality Control for Polylactic acid Production

et al. 2016

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Polylactic acid (PLA) is a very promising biodegradable, renewable, and biocompatible polymer. Aside from its production, its application field is also increasing, with use not only in commodity applications but also as durables and in biomedicine. In the current PLA production scheme, the most expensive part is not the polymerization itself but obtaining the building blocks lactic acid (LA) and lactide, the actual cyclic monomer for polymerization. Although the synthesis of LA and the polymerization have been studied systematically, reports of lactide synthesis are scarce. Most lactide synthesis methods are described in patent literature, and current energy-intensive, aselective industrial processes are based on archaic scientific literature. This Review, therefore, highlights new methods with a technical comparison and description of the different approaches. Water-removal methodologies are compared, as this is a crucial factor in PLA production. Apart from the synthesis of lactide, this Review also emphasizes the use of chemically produced racemic lactic acid (esters) as a starting point in the PLA production scheme. Stereochemically tailored PLA can be produced according to such a strategy, giving access to various polymer properties.

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Section: Synthesis Of Lactidementioning

confidence: 99%

Lactide Synthesis and Chirality Control for Polylactic acid Production

et al. 2016

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“…In this study, we prepared a series of flat polymer films with epoxy-activated moieties to chemically link Candida antartica lipase B (CALB) onto surfaces. CALB was selected for this study due to its extraordinary potential as a catalyst for a wide-range of chemical transformations on both small organic molecules and, more recently, for polymerization reactions …”

Section: Introductionmentioning

confidence: 99%

Protein Immobilization on Epoxy-Activated Thin Polymer Films: Effect of Surface Wettability and Enzyme Loading

et al. 2008

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A series of epoxy-activated polymer films composed of poly(glycidyl methacrylate/butyl methacrylate/hydroxyethyl methacrylate) were prepared. Variation in comonomer composition allowed exploration of relationships between surface wettability and Candida antartica lipase B (CALB) binding to surfaces. By changing solvents and polymer concentrations, suitable conditions were developed for preparation by spin-coating of uniform thin films. Film roughness determined by AFM after incubation in PBS buffer for 2 days was less than 1 nm. The occurrence of single CALB molecules and CALB aggregates at surfaces was determined by AFM imaging and measurements of volume. Absolute numbers of protein monomers and multimers at surfaces were used to determine values of CALB specific activity. Increased film wettability, as the water contact angle of films increased from 420 to 550, resulted in a decreased total number of immobilized CALB molecules. With further increases in the water contact angle of films from 55 degrees to 63 degrees, there was an increased tendency of CALB molecules to form aggregates on surfaces. On all flat surfaces, two height populations, differing by more than 30%, were observed from height distribution curves. They are attributed to changes in protein conformation and/or orientation caused by protein-surface and protein-protein interactions. The fraction of molecules in these populations changed as a function of film water contact angle. The enzyme activity of immobilized films was determined by measuring CALB-catalyzed hydrolysis of p-nitrophenyl butyrate. Total enzyme specific activity decreased by decreasing film hydrophobicity.

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“…Jeon et al have shown that CALB has a good activity for the ring opening reaction of both D,D-and L,L-lactides. 17 This indicates that the initiation step proceeds without problems and the low activity of CALB towards the ROP of lactides occurs during the propagation step (deacylation with the growing polymer as an acyl acceptor). In order to design a more active enzyme towards the D,D-lactide, a molecular modelling study was done.…”

mentioning

confidence: 97%