@article { ISI:000255130000001, title = {Lipase enzyme immobilization on synthetic beaded macroporous copolymers for kinetic resolution of chiral drugs intermediates}, journal = {Process Biochemistry}, volume = {43}, number = {4}, year = {2008}, month = {APR}, pages = {321-330}, publisher = {ELSEVIER SCI LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

Lipase isolated from Arthrobacter sp. (bacterial strain, MTCC No. 5125) at RRL Jammu, being used for various process development. Arthrobacter sp. lipase (ABL) now has been immobilized on synthetic polymers and reused many a times. In this investigation number of various synthetic macroporous alkylated glycidyl epoxy copolymers with varying hydrophobicity, pore volume and surface area were prepared and used for this study. Among all the polymers prepared and used only two epoxy polymers GMA-EGDM 75-20(I) and GMA-EGDM 75-30(I) with particle size in the range of 150-450 nm, epoxy groups 80 and 70\%, tertiary amino groups 20 and 30\% was found suitable for immobilization of lipase (ABL). Dibutyl amine (DBA) incorporation created an internal pore radii 20-50 nm and hydrophobic microenvironment in both the polymers for binding the enzyme, which led to improvement in stability and enatioselectivity in racemic resolution process especially by binding to one of the isomers. The optimal ABL binding capacity of polymer GMA-EGDM 75-20(I) was 60 units, 34 mg protein and GMA-EGDM 75-30(l) was 36 units, 21 mg protein/g polymer. The immobilized lipase matrices displayed enhanced pH, thermal, organic solvent and long-term storage stability. Both the immobilized enzyme matrices were tested firstly for the hydrolysis of triglycerides using tributyrin as substrate. After testing, both the matrices were reused for racemic resolution of ethyl-3-hydroxy-3-phenyl propanoate (fluoxetine intermediate, an antidepressant drug) and racemic chiral auxiliary, acetyl-1-phenyl ethanol (intermediate of many chiral drugs) for 15 cycles. These immobilized lipase matrices have shown very high stability on recycling, high-enantioselectivity, high conversion and faster recovery of product compare to free enzyme, therefore these matrices may find use in kinetic resolution process developments. (C) 2007 Elsevier Ltd. All rights reserved.

}, keywords = {1-phenyl ethanol and enantioselectivity, chiral resolution, enantiomeric excess (ee), ethyl-3-hydroxy-3-phenyl propanoate, Immobilization, Lipase}, issn = {1359-5113}, doi = {10.1016/j.procbio.2007.11.019}, author = {Bhushan, Indu and Parshad, Rajinder and Qazi, Gulam Nabi and Ingavle, Ganesh C. and Rajan, C. R. and Ponrathnam, Surendera and Gupta, Vijay Kumar} } @article { ISI:000300036000006, title = {Preparation of cross-linked enzyme aggregates of L-aminoacylase via co-aggregation with polyethyleneimine}, journal = {Journal of Molecular Catalysis B-Enzymatic}, volume = {74}, number = {3-4}, year = {2012}, month = {FEB}, pages = {184-191}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

L-Aminoacylase from Aspergillus melleus was co-aggregated with polyethyleneimine and subsequently cross-linked with glutaraldehyde to obtain aminoacylase-polyethyleneimine cross-linked enzyme aggregates (termed as AP-CLEA). Under the optimum conditions, AP-CLEA expressed 74.9\% activity recovery and 81.2\% aggregation yield. The said method of co-aggregation and cross-linking significantly improved the catalytic stability of L-aminoacylase with respect to temperature and storage. AP-CLEA were employed for enantioselective synthesis of three unnatural amino acids (namely: phenylglycine, homophenylalanine and 2-naphthylalanine) via chiral resolution of their ester-. amide- and N-acetyl derivatives. The enantioselectivity of AP-CLEA was the highest for hydrolysis of amino acid amides; was moderate for hydrolysis of N-acetyl amino acids and was the least for hydrolysis of amino acid esters. Furthermore, AP-CLEA were found to retain more than 92\% of the initial activity after five consecutive batches of (RS)-homophenylalanine hydrolysis suggesting an adequate operational stability of the biocatalyst. (C) 2011 Elsevier B.V. All rights reserved.

}, keywords = {chiral resolution, Cross-linked enzyme aggregates, L-Aminoacylase, Polyethyleneimine, Unnatural amino acids}, issn = {1381-1177}, doi = {10.1016/j.molcatb.2011.10.003}, author = {Vaidya, Bhalchandra K. and Kuwar, Suyog S. and Golegaonkar, Sandeep B. and Nene, Sanjay N.} } @article { ISI:000340469800024, title = {Highly efficient chiral resolution of DL-arginine by cocrystal formation followed by recrystallization under preferential-enrichment conditions}, journal = {Chemistry-A European Journal}, volume = {20}, number = {33}, year = {2014}, month = {AUG}, pages = {10343-10350}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

An excellent chiral symmetry-breaking spontaneous enantiomeric resolution phenomenon, denoted preferential enrichment, was observed on recrystallization of the 1:1 cocrystal of dl-arginine and fumaric acid, which is classified as a racemic compound crystal with a high eutectic ee value (\>95\%), under non-equilibrium crystallization conditions. On the basis of temperature-controlled video microscopy and in situ time-resolved solid-state (CNMR)-C-13 spectroscopic studies on the crystallization process, a new mechanism of phase transition that can induce preferential enrichment is proposed.

}, keywords = {Amino acids, chiral resolution, cocrystals, Crystal growth, phase transitions}, issn = {0947-6539}, doi = {10.1002/chem.201402446}, author = {Iwama, Sekai and Kuyama, Kazunori and Mori, Yuko and Manoj, Kochunnoonny and Gonnade, Rajesh G. and Suzuki, Katsuaki and Hughes, Colan E. and Williams, P. Andrew and Harris, Kenneth D. M. and Veesler, Stephane and Takahashi, Hiroki and Tsue, Hirohito and Tamura, Rui} } @article { ISI:000356370500002, title = {Preferential enrichment of DL-leucine using cocrystal formation with oxalic acid under nonequilibrium crystallization conditions}, journal = {Chirality}, volume = {27}, number = {7}, year = {2015}, month = {JUL}, pages = {405-410}, publisher = {WILEY-BLACKWELL}, address = {111 RIVER ST, HOBOKEN 07030-5774, NJ USA}, abstract = {

By utilizing the preferential enrichment (PE) technique, we achieved an improved enantiomeric resolution of DL-leucine (Leu) using a 1:1 cocrystal (DL-1) of DL-Leu and oxalic acid. The crystal structure analysis of DL-1 indicated the occurrence of a novel type of phase transition and subsequent preferential redissolution of one enantiomer from the resulting crystals into solution. Chirality 27:405-410 2015. (c) 2015 Wiley Periodicals, Inc.

}, keywords = {chiral resolution, cocrystal formation, leucine, phase transition, preferential enrichment}, issn = {0899-0042}, doi = {10.1002/chir.22431}, author = {Manoj, Kochunnoonny and Takahashi, Hiroki and Morita, Yoko and Gonnade, Rajesh G. and Iwama, Sekai and Tsue, Hirohito and Tamura, Rui} }