Deproteination of chrome waste by washing and enzymatic hydrolysis / J. Kupec in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVII, N° 9 (09/2002)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVII, N° 9 (09/2002) . - p. 349-354 Titre : Deproteination of chrome waste by washing and enzymatic hydrolysis Type de document : texte imprimé Auteurs : J. Kupec, Auteur ; M. Dvorackova, Auteur ; S. Rudlova, Auteur ; J. Ru, Auteur ; Karel Kolomaznik, Auteur Année de publication : 2002 Article en page(s) : p. 349-354 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Waste from the manufacture of chrome-tanned leathers (so-called shavings) can be processed (apart from alkaline or acid breakdown) by enzymatic hydrolysis employing alkaline proteases. Under mild reaction conditions, a soluble collagen hydrolyzate is formed and a solid fraction (so-called chrome cake) with high chromium content is formed after filtration. Further use of the chrome cake, e.g., tanning bath recycling, necessitates a maximum possible reduction in the protein fraction. This work performed deproteination of the chrome cake by decantation washing with water and enzymatic hydrolysis. Decantation washing of the chrome cake obtained after two-stage enzymatic hydrolysis of chrome-tanned shavings was performed six times with drinking water at laboratory temperature. A reduction in protein content occurs, as was proved by chemical analysis of chrome cakes prior to and after washing. Further deproteination of the chrome cake so washed (hence disposed of soluble part) was executed by means of additional enzymatic hydrolysis with ESPERASE and TRYPSIN. It was proved that further deproteination of chrome cake proceeded from this treatment even under very low concentrations of enzymes. En ligne : https://drive.google.com/file/d/19x9BcSXr3A1IglN1MkY0g87ql7pSMZaA/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4272 [article]

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Kinetics of alkaline hydrolysis of the insoluble protein fraction following enzymatic hydrolysis of chrome-tanned shavings / J. Hrncirik in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. C, N° 1 (01/2005)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. C, N° 1 (01/2005) . - p. 1-7 Titre : Kinetics of alkaline hydrolysis of the insoluble protein fraction following enzymatic hydrolysis of chrome-tanned shavings Type de document : texte imprimé Auteurs : J. Hrncirik, Auteur ; Karel Kolomaznik, Auteur ; J. Kupec, Auteur ; F. Hruska, Auteur ; M. Dvorackova, Auteur Année de publication : 2005 Article en page(s) : p. 1-7 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The problem of using chrome-tanned wastes (namely shavings) has been the subject of a number of reports. One path is enzymatic hydrolysis with possible utilization of both the protein fraction as well as chromium. After hydrolysis and subsequent filtration, a so-called filter (or chrome) cake is formed, which is composed of hydrated Cr2O3 heavily contaminated with protein products of hydrolysis (removable, e.g. in washing) as well as with a non-hydrolysable fraction. The fraction requires breaking down, e.g. with strong alkali, as was performed in tests conducted to provide data for evaluating hydrolysis kinetics. Applying a number of simplifying assumptions, efforts were directed to expressing formal kinetics of this alkaline hydrolysis with a KOH solution. According to calculations, the reaction appears to agree well with a second-order reaction, with effective values of rate constant c = 3.9.10-3 l/(mol.s) and activation energy Ea = 130 kJ/mol at hydrolysis temperature of 116°C. En ligne : https://drive.google.com/file/d/1oU3ce67tRFLR-MZNtxcMLIOJrrgMn2wP/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4084 [article]

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Testing aerobic degredation of the protein portion of filter cake after filtration of chrome tanned waste / M. Dvorackova in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CII, N° 3 (03/2007)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CII, N° 3 (03/2007) . - p. 77-84 Titre : Testing aerobic degredation of the protein portion of filter cake after filtration of chrome tanned waste Type de document : texte imprimé Auteurs : M. Dvorackova, Auteur ; J. Kupec, Auteur ; H. Mikulcakova, Auteur Année de publication : 2007 Article en page(s) : p. 77-84 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : An example of utilizing tanning waste as a secondary raw material is enzymatic hydrolysis of chrome shavings, the result of which is collagen hydrolysate (commercially applicable ) and filter cake containing hydrated Cr2O3 contaminated with collagen residues. With a view to further potential utilisation of chrome cake, the content of collagen portion has to be reduced to a minimum. A possible solution, the subject of this presented work, is removal of the collagen portion through aerobic biological degradation in an aqueous or soil environment. This process was examined by means of biochemical oxygen consumption (standard CSN EN ISO 9408) and carbon dioxide production expressed as a percentage of theoretical production (standard ASTM 5209-92). The source of micro organisms was the commercially produced soil substrate and a soil extract prepared there from for inoculating aqueous environment. Using the described conditions, it was found that the collagen portion is removed from aqueous environment by 83% and from the soil by 58% (in approximately 80 hours). Due to its insolubility, chromic oxide does not exhibit toxic influence. En ligne : https://drive.google.com/file/d/1m-7GfH0_gaHisUVa3t9aQr1rr8svwfln/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3363 [article]

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