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Construction of a chrome-free tanning system based on highly-oxidized starch–zirconium complexes / Yue Yu in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXVII, N° 3 (03/2022)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXVII, N° 3 (03/2022) . - p. 87-95 Titre : Construction of a chrome-free tanning system based on highly-oxidized starch–zirconium complexes Type de document : texte imprimé Auteurs : Yue Yu, Auteur ; Hui Wang, Auteur ; Ya-Nan Wang, Auteur ; Jianfei Zhou, Auteur ; Bi Shi, Auteur Année de publication : 2022 Article en page(s) : p. 87-95 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Amidons Biodégradation Croûte (cuir) On entend par "cuir en croûte" des cuirs ayant subi les opérations jusqu'au tannage, à l'exclusion de toute opération de corroyage ou de finissage, mais qui, par opposition aux wet-blue ont été séchés. Cuirs et peaux -- Propriétés physiques Eaux usées -- Analyse Granulométrie Post-tannage Taille des particules Tannage chrome free Tannage combiné Le tannage combiné se dit des tannages qui allient deux familles ou genre de tannage pour obtenir un résultat additionnant les qualités complémentaires des tannins mis en Å“uvre par exemple Chrome-Végétal ou Chrome-Synthétique Zirconium Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Chrome-free leather manufacture is one of the major focuses of leather industry. In this work, a chrome-free tanning system based on highly-oxidized starch–zirconium complexes (HOS–Zr) was constructed. Particle size and charge properties analyses revealed that the small size (2.5 nm) and the low cationic species content (45.1%) of HOS–Zr at low pH facilitated its uniform penetration in leather at the initial stage of tanning, and the large size (89–169 nm) and the high cationic species content (77.5%) of HOS–Zr after basification contributed to its stable crosslinking between collagen fibers. A 3% HOS–Zr offer (based on the weight of ZrO2) imparted wet white with sufficient tanning effect. The physical properties of HOS–Zr crust leather were remarkably better than those of lactic acid–zirconium crust leather and were comparable to those of chrome crust leather. Wastewater in HOS–Zr tanning system showed a reduction in TOC load by 40.0% and higher biodegradability compared with chrome tanning system. As a result, this work provided a practical and sustainable approach to eliminate chrome in leather manufacture. Note de contenu : - EXPERIMENTAL : Materials - Optimization of HOS-Zr tanning system - Particle size analysis - Charge properties analysis - Tanning trials - RESULTS AND DISCUSSION : Optimization of HOS-Zr-tanning system - Particle soze of HOS-Zr - Charge properties of Zr complexes - Comprehensive evaluation of the tanning performance of HOS-Zr - Table 1 : La-Zr and HOS-Zr tanning process - Table 2 : conventional chrome tanning process - Table 3 : Post-tanning process - Table 4 : Properties of tanned leathers - Table 5 : Physical properties o fcrust leathers - Table 6 : Pollution loads in tanning and post-tanning wastewaters (unit: kg/ton of pickled hide) - Table 7 : Biodegradability of tanning and post-tanning wastewaters En ligne : https://drive.google.com/file/d/1VmQIPtNQ6vZECS63DGWb4kMJcZEwDYNN/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37599 [article]

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A novel approach of removing externally attached debris from animal carcass to ensure meat safety and byproduct quality / Majher I. Sarker in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXVII, N° 3 (03/2022)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXVII, N° 3 (03/2022) . - p. 96-103 Titre : A novel approach of removing externally attached debris from animal carcass to ensure meat safety and byproduct quality Type de document : texte imprimé Auteurs : Majher I. Sarker, Auteur ; Cheng-Kung Liu, Auteur Année de publication : 2022 Article en page(s) : p. 96-103 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Bactéries -- Comptage Carcasses -- Décontamination Cuirs et peaux -- Propriétés mécaniques Cuirs et peaux de bovins Désinfectants Evaluation Formulation (Génie chimique) Nettoyage par pulvérisation Peaux brutes -- Nettoyage Statistique Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : In this study, a formulation and technique are developed to be used for cattle carcass decontamination prior to removal of hide in a commercially preferred time-frame to ensure meat safety and byproduct quality. This formulation offers deep cleaning on carcass surface by removing debris including manure/mud balls which are firmly attached to the hair of animal hide harboring pathogens like Salmonella and Escherichia coli. Survival of such pathogens can facilitate cross-contamination of the underlying meat and meat-processing equipment in the packing plant posing a challenge to the meat industry as well as public-health. Also, the attached adobe type mud/manure balls have potential to create holes on the hide during leather processing which degrades byproduct’s quality. Formulation was sprayed on cattle’s hide and the attached debris were brushed off from the surface. The formulation was found very efficient in cleaning the hide surface both at 5 and 8 min treatments. The highest of aerobic, Escherichia coli and Salmonella populations were reduced by 8.71, 3.63 and 3.19 Log CFU/50 in 2 , respectively when compared to water-wash. The efficacy of formulation can be optimized by adjusting its concentration and treatment time. Post-leather analysis showed no detrimental impact on byproduct caused by the formulation. Note de contenu : - MATERIALS AND METHODS : Hide preparation - Preparation of decontamination formulation - Spray treatment on bovine hide panels - Manure/mud balls removing protocol - Microbial testing - Leather and quality evaluation - Statistical analysis - RESULTS AND DISCUSSION : Efficacy of formulation in reducing bacterial population from hide surface - Aerobic bacteria colony count - Escherichia coli colony count - Salmonella colony count - Post-leather analysis - Table 1 : Composition of carcass decontamination formulation - Table 2 : Survival of nature-borne bacteria (Aerobic, escherichia coli and Salmonella) on bovine hide panels following the debris removing treatment - Table 3 : Mechanical properties of crush leather panels produced from water (control) and formulation treated hide pieces DOI : https://doi.org/10.34314/jalca.v117i3.4888 En ligne : https://drive.google.com/file/d/1Lbep5hozSSqvTZIsp5LBQX5aZsYuwwxy/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37600 [article]

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Efficient removal of ammonia-nitrogen from deliming effluent by using magnesium ammonium phosphate precipitation method / Hao Wang in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXVII, N° 3 (03/2022)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXVII, N° 3 (03/2022) . - p. 104-112 Titre : Efficient removal of ammonia-nitrogen from deliming effluent by using magnesium ammonium phosphate precipitation method Type de document : texte imprimé Auteurs : Hao Wang, Auteur ; Chao Lei, Auteur ; Yunhang Zeng, Auteur ; Hongguang Guo, Auteur ; Bi Shi, Auteur Année de publication : 2022 Article en page(s) : p. 104-112 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Azote ammoniacal Caractérisation Cuirs et peaux Déchets industriels -- Elimination Eaux usées -- Epuration pH Phosphate d'ammonium Phosphate de magnésium Le terme phosphate de magnésium est le nom générique pour les sels inorganiques de magnésium issus de l'acide phosphorique. Leur formule est : - le dihydrogénophosphate de magnésium (Mg(H2PO4)2) ; - l'hydrogénophosphate de magnésium (MgHPO4) ; - le phosphate de magnésium (proprement dit) ou phosphate de trimagnésium (Mg3(PO4)2 Ils incorporent éventuellement des molécules d'eau de cristallisation ; par exemple, le phosphate de magnésium tribasique (Mg3(PO4)2⋅nH2O) peut contenir 4, 5 ou 8 molécules d'eau. La bobierrite (it) est la forme minérale naturelle du phosphate de magnésium octahydraté. L'hydrogénophosphate de magnésium trihydraté se présente sous la forme d'une poudre blanche cristalline. La newbéryite est sa forme minérale naturelle. Les phosphates de magnésium entrent dans la composition du tissu osseux. (Wikipedia) Précipitation (chimie) Tannage -- Déchets Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Ammonia nitrogen (NH 3 -N) pollutant has received much attention in the leather industry. An efficient strategy for removal of NH 3 -N from tannery wastewater was proposed by using a magnesium ammonium phosphate (MAP) precipitation method to remove NH 3 -N from deliming effluent with the highest NH 3 -N concentration among all leather-making effluents. Results showed that approximately 80% of NH 3 -N was removed from deliming effluent when reacting at P/Mg/N mole ratio of 1.2:1.2:1.0 and pH 9.5 for 20 min. The NH 3 -N and total nitrogen concentrations of tannery wastewater (a composite wastewater of all leather-making effluents) sharply decreased by treating deliming effluent with MAP precipitation, which greatly improved the biological treatment efficiency of tannery wastewater. The residual concentration of NH 3 -N in the treated tannery wastewater was less than 2 mg/L. The total phosphorus concentration of tannery wastewater increased by less than 0.4 mg/L, indicating that secondary pollution of phosphorus did not occur after MAP precipitation treatment. Note de contenu : - EXPERIMENTAL : Materials - Effect of pH adjustment method on NH3-N removal efficency - Optimization of MAP precipitation method for removal of NH3-N from deliming effluent - Effect of P/N - Effect of Mg/N - Effect of reaction pH - Effect of reaction time - X-ray diffraction analysis of precipitate - Aerobic bological treatment of simulated tannery wastewater - RESULTS AND DISCUSSION : Effect of pH adjustment method on NH3-H removal efficiency - Effects of reaction conditions on the removal of NH3-N from deliming effluent byusing MAP precipitation method - Characterization of precipitation - Effect of MAP precipitation method on the biological treatment of tannery wastewater - Table 1 : Wastewater sampling from leather-making procedures - Table 2 : Effect of pH adjustment method on nH3-N removal efficiency - Table 3 : Concentrations of NH3-N, TOC, TN, and TP in simulated tannery wastewater before and after aerobic biological treatment En ligne : https://drive.google.com/file/d/1x6437XHaUBXbfG44KKIBz68wrvyhOs4J/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37601 [article]

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Heterologous expression of alkaline metalloproteinases in bacillus subtilis sck6 for eco-friendly enzymatic unhairing of goatskins / Shihao Zhang in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXVII, N° 3 (03/2022)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXVII, N° 3 (03/2022) . - p. 113-123 Titre : Heterologous expression of alkaline metalloproteinases in bacillus subtilis sck6 for eco-friendly enzymatic unhairing of goatskins Type de document : texte imprimé Auteurs : Shihao Zhang, Auteur ; Ruoshi Zhang, Auteur ; Xiaoguang Li, Auteur ; Zhe Xu, Auteur ; Yongqiang Tian, Auteur Année de publication : 2022 Article en page(s) : p. 113-123 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Caractérisation Cuirs et peaux -- Propriétés mécaniques Cuirs et peaux de chèvres Epilage enzymatique Matériaux -- Coloration Métalloprotéinases Wet-blue (tannage) Peau tannée au chrome (le chrome donne une couleur bleue) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : In this study, alkaline metalloprotease gene 1067 was cloned from Planococcus halotolerans SCU63T and heterologously expressed in Bacillus subtilis SCK6. Using Luria Bertani (LB) broth medium as the initial medium, the optimal medium was obtained through a series of fermentation and culture optimization (g/L): yeast extract (10), soybean powder (15), urea (20), potassium chloride (6.7), calcium chloride (13.3), NaCl (10). On the basis of the optimal medium, the highest enzymatic activity of 1259.21 U/mL could be obtained by culturing at 30°C for 40 h. with pH 8, inoculation amount of 4% and filling amount of 50 mL. EDTA inhibits protease activity and PMSF promotes it, indicating that it was a metalloprotease rather than a serine protease. The optimum reaction temperature of the protease is 70°C, and the optimum pH is 9. The metal ions Zn 2+, Co2+ and surfactant β-ME, Tween 80 can improve the activity of the protease. The results of unhairing, SEM and staining show that this metalloprotease can completely dehair goatskin. Compared with the conventional chemical method, the goatskin after enzymatic unhairing has softer texture and smoother surface, and there is no obvious damage to the goatskin. Note de contenu : - MATERIALS AND METHODS : Materials - Construction of recombinant plasmid and expression of 1067 in B. subtilis SCK6 - Optimization of fermentations conditions - Purification of protease 1067 - Enzyme assay - Analysis of enzymatic properties - Unhairing function of protease 1067 - Characterization of protease 1067 unhairing - RESULTS AND DISCUSSION : Construction of recombinant strain and identification of protease activity - Fermentation optimization - Purification and identification of protease 1067 - Effect of temperature on enzyme activity and stability - Effect of pH on enzyme activity and stability - Effect of metal ions on enzyme activity - Effects of chemicals on enzyme activity - Effect of organic solvents on enzyme activity - Analysis of unhairing - SEM and analysis of tissue staining - Table 1 : Factors and levels for RSM - Table 2 : ANOVA for quadratic model - Table 3 : Effect of metal ions on enzyme activity - Table 4 : Effect of chemicals on enzyme activity - Table 5 : Effect of solvents on enzyme activity - table 6 : Characterization of mechanical properties of wet blue skin DOI : https://doi.org/10.34314/jalca.v117i3.4892 En ligne : https://drive.google.com/file/d/1z4VjDZxnKDTJf0c5BtRxJKAwUieQ2jK9/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37602 [article]

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