High-efficiency bio-degreasing technology for leather making - Characterization of catalytic hydrolysis properties of lipases towards fats based on greasy skin powder substrate / Yongkang Luo in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXIV, N° 11 (11/2019)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXIV, N° 11 (11/2019) . - p. 429-439 Titre : High-efficiency bio-degreasing technology for leather making - Characterization of catalytic hydrolysis properties of lipases towards fats based on greasy skin powder substrate Type de document : texte imprimé Auteurs : Yongkang Luo, Auteur ; Shan Li, Auteur ; Shencai Pan, Auteur ; Chunxian Zhang, Auteur ; Cai Huang, Auteur ; Biyu Peng, Auteur Année de publication : 2019 Article en page(s) : p. 429-439 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Catalyse Cuirs et peaux -- Dégraissage Cuirs et peaux de porcs Hydrolyse Lipases Les lipases sont des enzymes hydrosolubles capables d'effectuer l'hydrolyse de fonctions esters et sont spécialisées dans la transformation de triglycéride en glycérol et en acides gras (lipolyse). À ce titre, elles constituent une sous-classe des estérases. Poudre de peaux Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Bio-degreasing technology based on the use of lipases has attracted more attention in the leather industry. Although lipases have been applied in leather making in the past, the previously reported lipase degreasing ratio is still not very high, i.e. less than 60%. In order to correctly understand the mechanism of lipase degreasing and to choose lipases and optimize the degreasing process for achieving efficient degreasing, a novel method of evaluating the catalytic hydrolysis properties of lipases towards skin fats based on a greasy skin powder substrate in an aqueous medium was established. This simulated the actual leather degreasing process and detected the amount of fatty acids produced. The special substrate was prepared; the determination conditions were optimized; then the performances of several typical lipases were evaluated. The results revealed that the lipase performances determined by the novel method were quite different from the standard method using emulsified olive oil substrate. There was a strong product-inhibition characteristic in the catalytic hydrolysis reaction of lipase, and the inhibition concentration of fatty acids varied with the lipase type, thus the maximum hydrolysis ratio of fats was only 67%. The lipases exhibited “super-activity” at pH around 9.5. This occurred because the fatty acids produced transformed into soluble soaps, thus the product-inhibition was weakened. According to the above results, a two-step lipase processing was made, i.e., beginning at pH 7.5 then 9.5. The hydrolysis ratio of fats rose to 82.57% from 46.23%, and the degreasing ratio increased from 50.78% to 89.68%. The new method with better repeatability can be used as a tool to correctly select lipases and optimize process parameters for lipase degreasing. Note de contenu : - EXPERIMENTAL : Materials - Preparation of the pigskin powder substrate rich in grease - Determination of lipase activity based on the prepared greasy skin powder substrate - Optimization of the method to terminate enzyme reaction - Water washing method - Hot drying method - Ethanol termination method - Acidification method - Acidification and water washing method - Absorption of fatty acids by pigskin powder after acidification - Extraction ratio of absorbed fatty acids by dichloromethane - Determination of lipase activity with the standard method - Evaluation of catalytic hydrolysis properties of some lipases towards fats in greasy skin powder - High-efficiency catalytic hydrolysis of fats by lipase and degreasing effect - RESULTS AND DISCUSSION : Main parameters of the prepared greasy pigskin powder substrate - Optimization of the method to terminate lipase reaction - Impact of acidification on the absorption of fatty acids by pigskin powder - Extraction ratio of fatty acid by dichloromethane - Comparison of the measuring result of lipase activity between the novel and standard methods - Impact of lipase concentration on lipolytic activities of lipases - Impact of reaction time on lipolytic activity of lipases - Effect of temperature on lipolytic hydrolysis of lipase En ligne : https://drive.google.com/file/d/1Db6VxRnqj3vXDlsp1w3HSE05ySOJRZs3/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=33255 [article]

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