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Biocatalytic designs for the conversion of renewable glycerol into glycerol carbonate as a value-added product

100%
Tudorache M., Ghemes G., Nae A., Matei E., Mercioniu I., Kemnitz E., Ritter B., Coman S., Parvulescu V.
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issue 12
1262-1270
EN
A comparative study of two different biocatalytic models, e.g. enzyme immobilized on magnetic particles (EIMP) and cross-linking enzyme aggregates onto magnetic particles (CLEMPA) was performed. The first model was designed as enzyme-immobilized on the magnetic particles surface (EIMP). The second model was constructed as a network structure with the enzyme aggregates and magnetic particles placed into the nodes and polyglutaraldehyde cross-linker as the network ledges. The design was called cross-linking enzyme aggregates onto magnetic particles (CLEMPA). The biocatalysts were prepared using lipase enzyme from Aspergillus niger for catalyzing the glycerol (Gly) conversion to glycerol carbonate (GlyC). The biocatalyst characteristics for both designs (EIMP and CLEMPA) were evaluated using scanning electron microscopy (SEM), laser light scattering (LLS) and UV-Vis techniques. The EIMP model was strongly influenced by the composition of the polymeric layer covering the particles surface, while the size of the magnetic particles affected mostly the CLEMPA design. Also, the biocatalytic capacity of the tested models was evaluated as maximum 52% Gly conversion with 90% GlyC selectivity for EIMP, and 73% Gly conversion with 77% GlyC selectivity for CLEMPA. Both biocatalytic models were successfully used to prepare GlyC from “crude” glycerol collected directly from the biodiesel process (e.g. 49% Gly conversion with 91% GlyC selectivity for EIMP and 70% Gly conversion with 80% GlyC selectivity for CLEMPA).
2
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Bioreduction of fluoroacetophenone derivatives by endophytic fungi isolated from the marine red alga Bostrychia radicans

75%
Mouad A. M., de Oliveira A. L. L., Debonsi H. M., Porto A. L. M.
Biocatalysis
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2014
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vol. 1
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issue 1
EN
Four endophytic fungi isolated from the marine red alga Bostrychia radicans identified as Botryosphaeria sp. CBMAI 1197, Eutypella sp. CBMAI 1196, Hidropisphaera sp. CBMAI 1194 and Xylaria sp. CBMAI 1195 catalyzed the asymmetric bioreduction of fluoroacetophenone derivatives 1-3 to the corresponding fluorophenylalcohols 1a-3a. In the reduction reactions of 2,2,2-trifluoro-1-phenylethanone 1, all the marine fungi produced exclusively the (S)-2,2,2-trifluoro- 1-phenylethanol 1a with > 99% ee. The fungus Botryosphaeria sp. CBMAI 1197 exhibited the best enzymatic potential, leading to the highest conversion values (up to > 99%). The biocatalyst Botryosphaeria sp. CBMAI 1197 also presented active enzymes in reactions with the substrates 1-(2-(trifluoromethyl)phenyl) ethanone (2) and 1-(2,4,5-trifluorophenyl)ethanone (3), producing the respective chiral alcohols S-2a and R-3a with > 99% ee. Additionally, the fungus Hidropisphaera sp. CBMAI 1194 yielded 100% of conversion of the ketone 3 to the corresponding S-alcohol 3a, with 53% ee.
3
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Biocatalytic Acetylation of Primary Amines by Lipases under Orbital Shaking and Microwave Radiation

75%
Araújo Y. J. K., Porto A. L. M.
Biocatalysis
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2014
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vol. 1
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issue 1
EN
This paper addresses the effects of the concentration of lipases, temperature and solvent on the enzymatic acetylation of primary amines. (±)-Heptan-2-amine 1, (±)-4-phenylbutan-2-amine 2, (±)-1,2,3,4-tetrahydronaphthalen-1-amine 3 and (±)-2-methylcyclohexan-1-amine 4 were acetylated using 11 lipases to obtain amides under orbital shaking and microwave radiation. Under microwave radiation the same amines were acetylated only using the CALB. (±)-Heptan-2-amine 1 was subjected to kinetic resolution, under orbital shaking for 7 h employing CALB and ethyl acetate as acylating agent, and converted into (R)-N- (heptan-2-yl)acetamide 5 (c = 42%, 88% eep, hexane c = 52%, 81% eep, isopropyl ether; c = 40%, 65% eep, toluene). The reaction was fast (15 s) under microwave radiation in hexane and yielded acetamide 4 in high conversion (c = 91%), but without selectivity (5% eep).
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