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001-es BibID:	BIBFORM084756
Első szerző:	Todea, Anamaria
Cím:	Optimization of enzymatic ring-opening copolymerizations involving delta-gluconolactone as monomer by experimental design / Anamaria Todea, Emese Biro, Valentin Badea, Cristina Paul, Adinela Cimporescu, Lajos Nagy, Sándor Kéki, Geza Bandur, Carmen Boeriu, Francisc Péter
Dátum:	2014
ISSN:	0033-4545 1365-3075
Megjegyzések:	Enzymatic incorporation of carbohydrate-derived monomer units into hydrophobic polyester backbones represents a promising alternative to obtain new biodegradable oligomers and polymers. Immobilized lipases are efficient biocatalysts for copolymerization of β-butyrolactone and delta-gluconolactone, but only a systematic optimization study was able to highlight the influence of the main reaction parameters on the polymerization degree and on the relative copolymer content of the product. Therefore, experimental design was employed for determination of the optimal ring-opening copolymerization conditions in solventless reaction systems, at temperatures up to 80 °C. The obtained products, cyclic and linear polyesters, have been characterized by FT-IR, MALDI-TOF MS, NMR, and TG analysis, demonstrating the incorporation of gluconolactone unit(s) into the hydrophobic backbone of the polyester and the formation of new bio-based products.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk biocatalysis experimental design lipase modeling POC-2014 polymerization delta-gluconolactone
Megjelenés:	Pure And Applied Chemistry. - 86 : 11 (2014), p. 1781-1792. -
További szerzők:	Biro, Emese Badea, Valentin Paul, Cristina Cimporescu, Adinela Nagy Lajos (1979-) (vegyész) Kéki Sándor (1964-) (polimer kémikus) Bandur, Geza Boeriu, Carmen G. Péter, Francisc
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM084572
Első szerző:	Todea, Anamaria
Cím:	Biocatalytic synthesis of delta-gluconolactone and epsilon-caprolactone copolymers / Anamaria Todea, Valentin Badea, Nagy Lajos, Kéki Sándor, Carmen G. Boeriu, Francisc Péter
Dátum:	2014
ISSN:	0001-527X 1734-154X
Megjegyzések:	The biodegradability and biocompatibility properties of epsilon-caprolactone homopolymers place it as a valuable raw material, particularly for controlled drug delivery and tissue engineering applications. However, the usefulness of such materials is limited by their low hydrophilicity and slow biodegradation rate. In order to improve polycaprolactone properties and functionalities, copolymerization of epsilon-caprolactone with delta-gluconolactone was investigated. Since enzymatic reactions involving sugars are usually hindered by the low solubility of these compounds in common organic solvents, finding the best reaction medium was a major objective of this research. The optimal copolymerization conditions were set up by using different organic media (solvent and solvents mixtures), as well as solvent free systems that are able to dissolve (completely or partially) sugars, and are nontoxic for enzymes. Native and immobilized lipases by different immobilization techniques from Candida antarctica B and Thermomyces lanuginosus have been used as biocatalyst at 80 degrees C. Although the main copolymer amount was synthesized in DMSO:t-BuOH (20:80) medium, the highest polymerization degrees, up to 16 for the copolymer product, were achieved in solventless conditions. The products, cyclic and linear polyesters, have been characterized by FT-IR and MALDI-TOF MS analysis. The reaction product analysis revealed the formation of cyclic products that could be the major impediment of further increase of the chain length
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk ?-caprolactone d-gluconolactone lipases biopolymers
Megjelenés:	Acta Biochimica Polonica. - 61 : 2 (2014), p. 205-2010. -
További szerzők:	Badea, Valentin Nagy Lajos (1979-) (vegyész) Kéki Sándor (1964-) (polimer kémikus) Boeriu, Carmen G. Francisc Péter
Pályázati támogatás:	POSDRU/159/1.5/S/137070 Egyéb
Internet cím:	Szerző által megadott URL Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM104069
035-os BibID:	(WoS)000489104300028 (Scopus)85071906261 (cikkazonosító)1402
Első szerző:	Todea, Annamaria
Cím:	Biodegradable Oligoesters of epsilon-Caprolactone and 5-Hydroxymethyl-2-Furancarboxylic Acid Synthesized by Immobilized Lipases / Anamaria Todea, Ioan Bîtcan, Diana Aparaschivei, Iulia Păuşescu, Valentin Badea, Francisc Péter, Vasile Daniel Gherman, Gerlinde Rusu, Lajos Nagy, Sándor Kéki
Dátum:	2019
ISSN:	2073-4360
Megjegyzések:	Following the latest developments, bio-based polyesters, obtained from renewable raw materials, mainly carbohydrates, can be competitive for the fossil-based equivalents in various industries. In particular, the furan containing monomers are valuable alternatives for the synthesis of various new biomaterials, applicable in food additive, pharmaceutical and medical field. The utilization of lipases as biocatalysts for the synthesis of such polymeric compounds can overcome the disadvantages of high temperatures and metal catalysts, used by the chemical route. In this work, the enzymatic synthesis of new copolymers of ?-caprolactone and 5-hydroxymethyl-2-furancarboxylic acid has been investigated, using commercially available immobilized lipases from Candida antarctica B. The reactions were carried out in solvent-less systems, at temperatures up to 80 C. The structural analysis by MALDI TOF-MS, NMR, and FT-IR spectroscopy confirmed the formation of cyclic and linear oligoesters, with maximal polymerization degree of 24 and narrow molecular weight distribution (dispersity about 1.1). The operational stability of the biocatalyst was explored during several reuses, while thermal analysis (TG and DSC) indicated a lower thermal stability and higher melting point of the new products, compared to the poly(epsilon-caprolactone) homopolymer. The presence of the heterocyclic structure in the polymeric chain has promoted both the lipase-catalyzed degradation and the microbial degradation. Although, poly(epsilon-caprolactone) is a valuable biocompatible polymer with important therapeutic applications, some drawbacks such as low hydrophilicity, low melting point, and relatively slow biodegradability impeded its extensive utilization. In this regard the newly synthesized furan-based oligoesters could represent a "green" improvement route.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk copolymerization renewable oligoester lipase furan-based epsilon-caprolactone
Megjelenés:	Polymers. - 11 : 9 (2019), p. 1-17. -
További szerzők:	Bîtcan, Ioan Aparaschivei, Diana Pausescu, Iulia Badea, Valentin Francisc Péter Gherman, Vasile Daniel Rusu, Gerlinde Nagy Lajos (1979-) (vegyész) Kéki Sándor (1964-) (polimer kémikus)
Pályázati támogatás:	GINOP-2.3.3-15-2016-00021 GINOP
Internet cím:	DOI Intézményi repozitóriumban (DEA) tárolt változat
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