References of "Berezina, Nathalie"
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See detailSynthesis of poly(butylene succinate) through oligomerization–cyclization–ROP route
Labruyère, Céline; Talon, Olivier; Berezina, Nathalie et al

in RSC Advances (2014), 4(73), 38643-36848

The preparation of cyclic butylene succinate lactone via catalytic depolymerization of poly(butylene succinate) oligomers (OPBS) and conversion to high-molecular weight poly(butylene succinate) (PBS) via ... [more ▼]

The preparation of cyclic butylene succinate lactone via catalytic depolymerization of poly(butylene succinate) oligomers (OPBS) and conversion to high-molecular weight poly(butylene succinate) (PBS) via ring-opening polymerization (ROP) is described. OPBS was first synthesized by two-stage melt polycondensation, purified and characterized by size exclusion chromatography (SEC). Then, it was depolymerized under reduced pressure in a glass oven and the volatile fraction (VF) was collected and characterized. The butylene succinate lactones obtained by intramolecular transesterification were characterized by nuclear magnetic resonance (1H NMR) and mass spectrometry (MS). Their further successful ROP polymerization within 24 hours afforded the desired PBS with Mw of 65 000 g/mol and Đ of 2.2 [less ▲]

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See detailOptimization of Production and Preliminary Characterization of New Exopolysaccharides from Gluconacetobacter hansenii LMG1524
Valepyn, Emmanuel ULg; Berezina, Nathalie; Paquot, Michel ULg

in Advances in Microbiology (2012), 2(4), 488-496

The influence of different carbon and nitrogen sources, of ethanol concentration, the optimal pH, temperature and me-dium composition were evaluated on extracellular polysaccharides (EPS) synthesis and ... [more ▼]

The influence of different carbon and nitrogen sources, of ethanol concentration, the optimal pH, temperature and me-dium composition were evaluated on extracellular polysaccharides (EPS) synthesis and bacterial growth of Gluconace-tobacter hansenii LMG1524, and preliminary characterization of EPS was investigated. The highest EPS yields were obtained using glycerol and ammonium sulphate as carbon and nitrogen sources, respectively. The increase of ethanol concentration in the medium did not influence the EPS synthesis but reduced the bacterial growth. The optimum tem-perature and pH for polysaccharides production were respectively 25 °C and 5; whereas for cell growth were respec-tively 30 °C and 4. The optimal culture medium composition was determined as follows : 10 g/L sucrose, 0.892 g/L (NH4)2SO4, 0.34 g/L NaNO3, 3 mL acetic acid, 1.5 g/L KH2PO4, 1.5 g/L K2HPO4 and 0.6 g/L MgSO4. The polysaccha-rides produced were of 14 and 10 polymerization degrees (DP) and constituted mainly of glucose, galactose and man-nose, in relative percent of 36.36, 33.94 and 22.42, respectively. [less ▲]

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See detailLipase-catalyzed synthesis of L-cysteine glucosyl esters in organic media
Valepyn, Emmanuel ULg; Nys, Joël ULg; Richel, Aurore ULg et al

in Biocatalysis & Biotransformation (2011), 29(1), 25-30

New sugar amino acids were synthesized by enzymatic esterification of D -glucose with L -cysteine using immobilized lipase B from Candida antarctica in a mixed solvent system composed of 2-methyl-2 ... [more ▼]

New sugar amino acids were synthesized by enzymatic esterification of D -glucose with L -cysteine using immobilized lipase B from Candida antarctica in a mixed solvent system composed of 2-methyl-2-butanol and dimethyl sulfoxide. Addition of small quantities of water to the medium improved the glucose conversion yield by a factor of two. [less ▲]

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