This study reports the synthesis of a hybrid sol-gel material, based on organically modified sila... more This study reports the synthesis of a hybrid sol-gel material, based on organically modified silanes (ORMOSILs) with epoxy functional groups, and its application in the stabilization of lipase type B from Candida antarctica (CalB) through sol-gel entrapment. The key immobilization parameters in the sol-gel entrapment of lipase using epoxysilanes were optimized by the design of numerous experiments, demonstrating that glycidoxypropyl-trimethoxysilane can allow the formation of a matrix with excellent properties in view of the biocatalytic esterifications catalyzed by this lipase, at an enzyme loading of 25 g/mol of silane. The characterization of the immobilized biocatalyst and the correlation of its catalytic efficiency with the morphological and physicochemical properties of the sol-gel matrix was accomplished through scanning electron microscopy (SEM), fluorescence microscopy (FM), as well as thermogravimetric and differential thermal analysis (TGA/DTA). The operational and therma...
The EKR of some heteroaromatic secondary ethanols with tailored sol–gel immobilized lipases in ba... more The EKR of some heteroaromatic secondary ethanols with tailored sol–gel immobilized lipases in batch and continuous-flow reactors was studied. The productivity in continuous-flow mode is higher than in batch mode.
Remarkable developments have been achieved in recent decades in terms of the utilization of isola... more Remarkable developments have been achieved in recent decades in terms of the utilization of isolated enzymes as green alternative catalysts in polymer science [...]
Anthocyanidins, the aglycons of anthocyanins, are known, beyond their function in plants, also as... more Anthocyanidins, the aglycons of anthocyanins, are known, beyond their function in plants, also as compounds with a wide range of biological and pharmacological activities, including cytostatic effect against various cancer cells. The nature and position of the substituents in the flavylium cation is essential for such biological properties, as well as the equilibrium between the multistate of the different chemical species that are generated by the flavylium cation, including quinoidal base, hemiketal, and cis- and trans-chalcones. In this work, eight new flavylium derivatives were synthesized, characterized for confirmation of the structure by FT-IR and 2D-NMR, and investigated in vitro as possible cytostatic compounds against HCT116 and HepG2 cancer cells. The most active two compounds were explored for their halochromic properties that can influence the biological activity and subjected to molecular encapsulation in β-cyclodextrin derivatives in order to increase their solubility...
β-Galactosidase (β-gal), an important enzyme used in the food industry to hydrolyze milk and whey... more β-Galactosidase (β-gal), an important enzyme used in the food industry to hydrolyze milk and whey, was immobilized onto chitosan microparticles prepared by the emulsion crosslinking method. The immobilization conditions such as enzyme binding capacity of the microparticles, crosslinking agent concentration, and immobilization time were optimized. A 3% glutaraldehyde concentration was found as optimal and allowed an enzyme loading of 27 mg protein/g dry support. Reduction with sodium borohydride after the covalent attachment was beneficial for the catalytic activity, leading to a total activity yield of 23.5% related to the native Kluyveromyces lactis β-gal subjected to immobilization. The immobilized biocatalyst was characterized by pH dependence, thermostability and distribution of protein
An industrially manufactured recycled polyol, obtained by acidolysis process, was for the first t... more An industrially manufactured recycled polyol, obtained by acidolysis process, was for the first time proved to be a possible replacement of the reference fossil-based polyol in a low-density formulation suitable for industrial production of flexible polyurethane foams. The influence of increasing recycled polyol amounts on the properties of the polyurethane foam has been studied, also performing foam emission tests to evaluate the environmental impact. Using 10 pbw recycled polyol in the standard formulation, significant differences of the physical properties were not observed, but increase of the recycled polyol amount to 30 pbw led to a dramatic decrease of the foam air flow and a very tight foam. To overcome this drawback, N,N′-bis[3-(dimethylamino)propyl]urea was selected as tertiary amine catalyst, enabling the preservation of foam properties even at high recycled polyol level (30 pbw). Foam emission data demonstrated that this optimized foam formulation also led to an importan...
Recently, increased attention has been paid to natural sources as raw materials for the developme... more Recently, increased attention has been paid to natural sources as raw materials for the development of new added-value products. Flavonoids are a large family of polyphenols which include several classes based on their basic structure: flavanones, flavones, isoflavones, flavonols, flavanols, and anthocyanins. They have a multitude of biological properties, such as anti-inflammatory, antioxidant, antiviral, antimicrobial, anticancer, cardioprotective, and neuroprotective effects. Current trends of research and development on flavonoids relate to identification, extraction, isolation, physico-chemical characterization, and their applications to health benefits. This review presents an up-to-date survey of the most recent developments in the natural flavonoid classes, the biological activity of representative flavonoids, current extraction techniques, and perspectives.
This study reports the synthesis of a hybrid sol-gel material, based on organically modified sila... more This study reports the synthesis of a hybrid sol-gel material, based on organically modified silanes (ORMOSILs) with epoxy functional groups, and its application in the stabilization of lipase type B from Candida antarctica (CalB) through sol-gel entrapment. The key immobilization parameters in the sol-gel entrapment of lipase using epoxysilanes were optimized by the design of numerous experiments, demonstrating that glycidoxypropyl-trimethoxysilane can allow the formation of a matrix with excellent properties in view of the biocatalytic esterifications catalyzed by this lipase, at an enzyme loading of 25 g/mol of silane. The characterization of the immobilized biocatalyst and the correlation of its catalytic efficiency with the morphological and physicochemical properties of the sol-gel matrix was accomplished through scanning electron microscopy (SEM), fluorescence microscopy (FM), as well as thermogravimetric and differential thermal analysis (TGA/DTA). The operational and therma...
The EKR of some heteroaromatic secondary ethanols with tailored sol–gel immobilized lipases in ba... more The EKR of some heteroaromatic secondary ethanols with tailored sol–gel immobilized lipases in batch and continuous-flow reactors was studied. The productivity in continuous-flow mode is higher than in batch mode.
Remarkable developments have been achieved in recent decades in terms of the utilization of isola... more Remarkable developments have been achieved in recent decades in terms of the utilization of isolated enzymes as green alternative catalysts in polymer science [...]
Anthocyanidins, the aglycons of anthocyanins, are known, beyond their function in plants, also as... more Anthocyanidins, the aglycons of anthocyanins, are known, beyond their function in plants, also as compounds with a wide range of biological and pharmacological activities, including cytostatic effect against various cancer cells. The nature and position of the substituents in the flavylium cation is essential for such biological properties, as well as the equilibrium between the multistate of the different chemical species that are generated by the flavylium cation, including quinoidal base, hemiketal, and cis- and trans-chalcones. In this work, eight new flavylium derivatives were synthesized, characterized for confirmation of the structure by FT-IR and 2D-NMR, and investigated in vitro as possible cytostatic compounds against HCT116 and HepG2 cancer cells. The most active two compounds were explored for their halochromic properties that can influence the biological activity and subjected to molecular encapsulation in β-cyclodextrin derivatives in order to increase their solubility...
β-Galactosidase (β-gal), an important enzyme used in the food industry to hydrolyze milk and whey... more β-Galactosidase (β-gal), an important enzyme used in the food industry to hydrolyze milk and whey, was immobilized onto chitosan microparticles prepared by the emulsion crosslinking method. The immobilization conditions such as enzyme binding capacity of the microparticles, crosslinking agent concentration, and immobilization time were optimized. A 3% glutaraldehyde concentration was found as optimal and allowed an enzyme loading of 27 mg protein/g dry support. Reduction with sodium borohydride after the covalent attachment was beneficial for the catalytic activity, leading to a total activity yield of 23.5% related to the native Kluyveromyces lactis β-gal subjected to immobilization. The immobilized biocatalyst was characterized by pH dependence, thermostability and distribution of protein
An industrially manufactured recycled polyol, obtained by acidolysis process, was for the first t... more An industrially manufactured recycled polyol, obtained by acidolysis process, was for the first time proved to be a possible replacement of the reference fossil-based polyol in a low-density formulation suitable for industrial production of flexible polyurethane foams. The influence of increasing recycled polyol amounts on the properties of the polyurethane foam has been studied, also performing foam emission tests to evaluate the environmental impact. Using 10 pbw recycled polyol in the standard formulation, significant differences of the physical properties were not observed, but increase of the recycled polyol amount to 30 pbw led to a dramatic decrease of the foam air flow and a very tight foam. To overcome this drawback, N,N′-bis[3-(dimethylamino)propyl]urea was selected as tertiary amine catalyst, enabling the preservation of foam properties even at high recycled polyol level (30 pbw). Foam emission data demonstrated that this optimized foam formulation also led to an importan...
Recently, increased attention has been paid to natural sources as raw materials for the developme... more Recently, increased attention has been paid to natural sources as raw materials for the development of new added-value products. Flavonoids are a large family of polyphenols which include several classes based on their basic structure: flavanones, flavones, isoflavones, flavonols, flavanols, and anthocyanins. They have a multitude of biological properties, such as anti-inflammatory, antioxidant, antiviral, antimicrobial, anticancer, cardioprotective, and neuroprotective effects. Current trends of research and development on flavonoids relate to identification, extraction, isolation, physico-chemical characterization, and their applications to health benefits. This review presents an up-to-date survey of the most recent developments in the natural flavonoid classes, the biological activity of representative flavonoids, current extraction techniques, and perspectives.
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Papers by Francisc Peter