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The effect of anaerobic digestion on chrome sludge - A by - product of tanned leather waste / Nabanita Saha in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVIII, N° 7 (07/2003)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVIII, N° 7 (07/2003) . - p. 256-262 Titre : The effect of anaerobic digestion on chrome sludge - A by - product of tanned leather waste Type de document : texte imprimé Auteurs : Nabanita Saha, Auteur ; Karel Kolomaznik, Auteur ; Lubomir Saha, Auteur ; Martina Kresalkova, Auteur Année de publication : 2003 Article en page(s) : p. 256-262 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The leather industry is environmentally important as a user of a by-product of the meat industry. It is perceived as a consumer of resources and a producer of pollutants. The most serious problem is chrome tanned solid wastes, which are now under control through alkali-enzymatic hydrolysis treatment of chrome shavings. The main products of this hydrolytic reaction are gelable protein hydrolysate, enzymatic hydrolysate, and chrome sludge. In chrome sludge, the rest of the biomaterial is collagen protein. Approximately 20-40 % (on free moisture basis) is strongly bound as co-ordinate complex with chromium, which creats serious problems for further treatment of it to recover tanning salt. One possible solution is to decrease the content of collagen protein by anaerobic digestion, which is presented in this paper. The effect of anaerobic digestion on chrome sludge was observed under controlled conditions using different fermentation compositions of broth at 50°C for a 15 day incubation period. Sludge, inoculum and water at 3:1:1 ratio was determined to be the optimum fermentation composition from the bioconversion point-of-view. During anaerobic digestion, the content of biomaterial associated with the chrome sludge decreased while the quantity of free chromium increased. These observations were confirmed by attenuated total reflectance (ATR) using FTIR spectophotometric and scanning electron microscopic (SEM) analysis. En ligne : https://drive.google.com/file/d/1d3tHTWq3kcPMSWrvM8T_ii0mDUt2Vs7o/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4143 [article]

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Hydration in matrix stabilization of collagen fibres : relevance to mechanistic insight into tanning / Balaraman Madhan in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVIII, N° 7 (07/2003)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVIII, N° 7 (07/2003) . - p. 263-272 Titre : Hydration in matrix stabilization of collagen fibres : relevance to mechanistic insight into tanning Type de document : texte imprimé Auteurs : Balaraman Madhan, Auteur ; T. Ramasami, Auteur ; Balachandran Unni Nair, Auteur ; V. Subramanian, Auteur ; Jonnalagadda Raghava Rao, Auteur ; N. N. Fathima, Auteur Année de publication : 2003 Article en page(s) : p. 263-272 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Quantitative understanding of fundamental processes leading to tanning of collagenous tissues has attracted renewed interest in recent times. Although it is traditional to relate formation of crosslinks formed at angstromunit dimensions to increases in the hydrothermal stability of collagenous matrices, further understanding of long range order in collagen supra assembly induced by tanning molecule in nano scale dimensions is becoming more evident. Increases in hydrothermal stability of rat tail tendon fibres induced by precursors of vegetable tannins like catechin, quercetin and gallic acid have now been correlated. Molecular modeling approaches have been employed to simulate and estimate possible net increase in hydrogen bonding energies resulting from binding of collagen with the precursors of vegetable tannins. The stability of collagen fibres against degradation by collagenase has been previously quantitatively related to inhibition of collagenase by tannin molecules. Now an attempt has been made to understand the role of hydration and solvation phenomena in the theory of tanning. A series of thermochemical and NMR investigations have been made with a view to understand at least semi-quantitatively, the role of structure and dynamics of water around collagenous fibres. The binding energies of the complexes of tannin precursors with the collagen-like peptide determined using molecular modeling study has been correlated with the denaturation temperature of tanned collagen and the relaxation times (T1 and T2) of water in tanned fibres. Experimental evidence for the influence of catechin, quercetin and gallic acid on structure and dynamics of free and bound water in collagen fibres has been presented. En ligne : https://drive.google.com/file/d/1Bdj_V5zMF4ugePRNnbyZcUVdRGCkgKnH/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4144 [article]

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A semi-empirical quantum mechanical modeling study on the interaction of collagen-like peptides with polyphenolic molecules : An attempt to gain insights into vegetable tanning / Balaraman Madhan in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVIII, N° 7 (07/2003)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVIII, N° 7 (07/2003) . - p. 273-278 Titre : A semi-empirical quantum mechanical modeling study on the interaction of collagen-like peptides with polyphenolic molecules : An attempt to gain insights into vegetable tanning Type de document : texte imprimé Auteurs : Balaraman Madhan, Auteur ; V. Subramanian, Auteur ; Jonnalagadda Raghava Rao, Auteur ; Balachandran Unni Nair, Auteur ; T. Ramasami, Auteur Année de publication : 2003 Article en page(s) : p. 273-278 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : A semi-empirical quantum mechanical PM3 hamiltonian based molecular modeling has been used to study the interactions of collagen-like peptide with polyphenolics. A collagen-like peptide 9-mer sequence has been built and interacted with the polyphenolic molecules. Most of the complexes of the peptide sequence and polyphenolic molecule exhibited hydrogen bonding. The binding energies of the complexes were in the range of 6.5 - 20 kcal/mol. Complexes of gallic acid exhibited the least binding energies. Epicatechin complexes exhibited higher binding energies with the collagen-like peptide sequence. En ligne : https://drive.google.com/file/d/1NKAhmRIfS0pZFdyQWs5Cphz-oIlJQsoI/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4145 [article]

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Determination of the collagen thermal transitions in chrome leather by TMA / Albert M. Manich in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVIII, N° 7 (07/2003)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVIII, N° 7 (07/2003) . - p. 279-284 Titre : Determination of the collagen thermal transitions in chrome leather by TMA Type de document : texte imprimé Auteurs : Albert M. Manich, Auteur ; Teresa Bosch, Auteur ; Josep Carilla, Auteur ; Jaime Cot, Auteur ; Agusti Marsal, Auteur ; Joan Sala, Auteur ; Pedro J. Celma, Auteur Année de publication : 2003 Article en page(s) : p. 279-284 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The collagen thermal transitions of bovine chrome leather were studied by thermomechanical analysis (TMA). The application of dynamical stresses under transverse compressive penetration and longitudinal extension modes allows us to determine the glass-transition temperature of collagen in conditioned and dried states and the denaturation temperature in dried state of collagen. The results agree with those obtained by differential scanning calorimetry (DSC) and thermogravimetry (TGA). The thermal transitions determined by TMA in transverse compressive penetration mode showed a good relationship with the origin and final application of leather. En ligne : https://drive.google.com/file/d/1Fs6tClG8Ajqq9TvgOQeQmWgFg2koxXqU/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4146 [article]

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