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Unhairing with proteolytic enzymes derived from Streptomyces griseus / Andrew G. Gehring in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVII, N° 10 (10/2002)
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Titre : Unhairing with proteolytic enzymes derived from Streptomyces griseus Type de document : texte imprimé Auteurs : Andrew G. Gehring, Auteur ; Chad E. Mazenko, Auteur ; William N. Marmer, Auteur ; Gary L. DiMaio, Auteur Année de publication : 2002 Article en page(s) : p. 406-411 Note générale : Bibliogr. Langues : Américain (ame) Résumé : A mixture of proteolytic enzymes derived from the bacterium, Streptomyces griseus, was used to unhair bovine hide pieces. The enzymatic unhairing was assisted by a 30-min pretreatment of the pieces with carbonate buffer and the inclusion of a common amphoteric surfactant (N, N-dimethyl-1-dodecanamine oxide) in the enzyme formulation. This unhairing process may serve as a replacement for the hairburn process that relies on hazardous sodium sulfide. The unhairing reaction consisted of drumming pretreated hide pieces with 0.5 mg/mL of the bacterial protease (in 1% N, N-dimethyl-1-dodecanamine oxide) for 4 hours at 37°C in a 200% float. This process causes the majority of hair to either fall out intact or to become extremely loose and hence readily removed through physical/mechanical means. Some fine hairs remain, thus requiring sharpening agents to be used in reliming to achieve total unhairing. Laboratory-scale studies using bovine hide pieces compared this enzymatic treatment to typical hairburn with sodium sulfide. The studies demonstrated that shrinkage temperature, physical properties, dye levelness, dye shading, and grain appearance were comparable if not better for the enzymatic unhairing. En ligne : https://drive.google.com/file/d/1TxoucXpfszNDUxQTkZ1Z0qx7a_eFHY80/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4269
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVII, N° 10 (10/2002) . - p. 406-411[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 001579 - Périodique Bibliothèque principale Documentaires Disponible Use of enzymatically modified gelatin and casein as fillers in leather processing ! / Maryann M. Taylor in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CI, N° 5 (05/2006)
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Titre : Use of enzymatically modified gelatin and casein as fillers in leather processing ! Type de document : texte imprimé Auteurs : Maryann M. Taylor, Auteur ; Eleanor M. Brown, Auteur ; William N. Marmer, Auteur ; Lorelei P. Bumanlag, Auteur Année de publication : 2006 Article en page(s) : p. 169-178 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Prior research from this laboratory demonstrated that chemically modified collagen byproducts could be used effectively as fillers during leather processing. The gelatins were reacted with glutaraldehyde and, after application to veiny leather, these highly polymerized gelatins did fill and more importantly were bound to the substrate. The applications were followed by using fluorescently labeled gelatin that was added to a stock solution and the final products were examined under a microscope that had the capability of showing that the gelatins fluoresce. In this present study, fluorescently labeled gelatins were polymerized by using microbial transglutaminase as the cross-linking agent and the reactions took place in either the leather itself or the samples were first prepared and then added to the leather. Furthermore, we wanted to see, based on results from our earlier experiments in which we produced biopolymers from enzyme-modified gelatin and casein, if these products could also be effective fillers. In these experiments, we labeled casein as well as the gelatin. Varying conditions were examined for optimal filling results. The results showed that indeed these enzymatically prepared products could be used effectively as fillers and moreover were bound to the leather and would not easily be removed during further processing. En ligne : https://drive.google.com/file/d/1bXAsNyNnq9yMRcAF5q_RaKQl_8W3yNTr/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4011
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CI, N° 5 (05/2006) . - p. 169-178[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 004807 - Périodique Bibliothèque principale Documentaires Disponible Vigorous proteolysis : reliming in the presence of an alkaline protease and bating (post-liming) with an extremophile protease / S. M. Mozersky in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVII, N° 4 (04/2002)
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Titre : Vigorous proteolysis : reliming in the presence of an alkaline protease and bating (post-liming) with an extremophile protease Type de document : texte imprimé Auteurs : S. M. Mozersky, Auteur ; William N. Marmer, Auteur ; O. Dale Allen, Auteur Année de publication : 2002 Article en page(s) : p. 150-155 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : As part of an investigation into the feasibility of removing from a hide some or all of its decorin while it is being processed into leather, we studied the effects on the physical characteristics of the leather of subjecting the hide to vigorous proteolysis. We used two proteolytic enzyme preparations, one during reliming, and the second for bating post liming. The first is a commercially produced alkaline protease (AP). Extending the work of Alexander in England and of Kronick at Eastern Regional Research Center, ARS, USDA, we found that, for each observed physical property, viz., tensile strength (Smax), Young's modulus (Y), and extensibility (E), the value for the AP-treated samples differed from the corresponding control value by < 6-8% (the least significant difference), thus demonstrating that AP does not adversely affect any of the three physical characteristics. The AP-treated hides are, however, substantially softer and more flexible than the controls. The second protease preparation is one that we made from a halophile selected because it does not produce collagenase. This protease is active in 4M NaCl at a mildly alkaline pH. Bating with the halophile protease in 4M NaCl was found to yield a leather with satisfactory physical characteristics (Smax, Y, and E). High salt concentration will be used experimentally to loosen the tight (albeit non-covalent) bonding of decorin to collagen, thus rendering the proteoglycan more susceptible to proteolysis and removal from the hide. En ligne : https://drive.google.com/file/d/1FkL6j13napjNATdHgURko2lna7B0vxEl/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4313
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVII, N° 4 (04/2002) . - p. 150-155[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 001573 - Périodique Bibliothèque principale Documentaires Disponible