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Low Carbon Products to Design Innovative Leather Processes. Part III: Optimization of an Eco-friendly Formulation Using Tara 
by A. Bacardit, J. Diaz, C. Casas and L. Olle
Volume: 110      Number: 9     Page: 302-309     Year: 2015
The aim of this work was to design a new pretanning formulation by using the fruit of the Tara tree (Cæsalpinia Spinosa) as the sole source of vegetable tannin. The innovative aspect of this work embodies a new-tailored tara product which gave its tannin the enhanced ability to readily penetrate the leather cross section, and thus made it unnecessary for the tanner to add aldehydes, syntans, other common vegetable tannins and mineral salts. Specifically, physical modifications had been developed in part II of this broad study to obtain a modified tara with a higher percentage of tannins and with a better ability to penetrate/fix in leather by sieving and milling (see Low carbon products to design innovative leather processes. Part I: determination of the optimal chemical modification of tara1 and Low carbon products to design innovative leather processes. Part II: determination of the optimal physical modification of tara).2 We developed in this work an innovative, eco-friendly and optimal wet white formulation which has a maximum offer to leather of 9% modified tara and a maximum 2% naphthalene sulphonic syntan dispersing agent.
 
 
Value Added Leather Auxiliaries from Paper and Pulp Industry Waste 
by M. Vedhanayagam, T. Teddy, K. Sreeram, J. Raghava Rao and B. Unni Nair
Volume: 110      Number: 9     Page: 295-301     Year: 2015
The present work involves the preparation of a retanning agent from the organics present in the black liquor generated by paper and pulp industry. Black liquor organics was extracted by using solvent extraction method and subsequently separated as acidic, non-acidic and organic compounds that were not degraded. Acidic and non acidic organics were sulfonated and further condensed with formaldehyde to obtain a product ideal for application. Sulfonation – condensation reactions were modulated to achieve particle size on par with that of commercial syntans. Condensed products from both acidic and non-acidic components were used in lieu of synthetic tanning agents in retanning. The final leathers exhibit offwhite color with good mechanical strength as compared to leathers from commercial phenolic syntan. This work reveals that the black liquor, which is a by-product of paper and pulp industry could through an innovative process, be turned into a retanning agent for leather processing. The product has the advantage of being able to replace phenol – a product with high market fluctuation.
 
 
Metal Organic Based Syntan for Multi-stage Leather Processing 
by G. Jayakumar, S. Sangeetha, K. Sreeram, J. Raghava Rao and B. Unni Nair
Volume: 110      Number: 9     Page: 288-294     Year: 2015
The leather industry in India and elsewhere have adopted a two stage processing methodology wherein hides/skins are processed up to wet blue in stage one, and subsequently converted to value added products in stage two. The process of rechroming carried out when wet blue leathers are sourced from various vendors thus attains significance. Many tanners prefer to employ chromium based synthetic tanning agents for rechroming, as against basic chromium sulfate, so as to provide for a tanning at higher pH values of above 3.5 – 4.0. Chromium based synthetic tanning agents in addition to employing masked chromium salts also provide for increased fullness to the leather. A significantly large number of these synthetic tanning agents are based on formaldehyde condensed aromatic intermediates, the use of which could result in the presence of free formaldehyde in the crust leathers. Instances of poorer raw material quality also call for the use of melamine-based syntans for preferential filling of the belly regions. In this work, the application of a chromium based melamine syntan devoid of the use of formaldehyde for condensation is reported. The product has been evaluated in tanning, rechroming and post tanning (as a retanning agent). In tanning, the product provides for a shrinkage temperature of 106oC, 3.25-3.75% Cr2O3 content (dry weight) alongside good belly filling. On use in rechroming or post tanning, the product provides for fuller leathers complete with physical properties meeting standard norms. The results indicate that the newly developed product has a significant scope in increasing the cutting value of the leathers by way of providing uniform substance alongside good tanning properties.
 
 
A New Marking System for Leather Based on Encapsulated DNA 
by Sandra Stenzel, Jorg Bohrisch, Michael Pach and Michael Meyer
Volume: 110      Number: 9     Page: 277-287     Year: 2015
The use of synthetic DNA as a marking system is a new traceability concept in the leather industry, especially for supplier and batch tracing. DNA is outstandingly suited for the usage as a marking system because of its code diversity, invisibility and doubtlessness. However, DNA labeling is a great challenge for products exposed to DNA damaging influences during their production, such as acidic pH, elevated temperatures in combination with high humidity or sunlight radiation. Leather is such a product. We attached single-strand DNA (ssDNA) to hydroxyapatite and enhanced the stability of these DNA particles by encapsulation in polystyrene-codivinylbenzene (PS-DVB) microcapsules. Furthermore, the ssDNA containing microcapsules were improved with functional groups on the surface of the capsule to irreversibly attach them to the collagen matrix of leather by chrome tanning. Laboratory scale tests using acidic conditions as well as elevated temperatures in the presence of high humidity showed that the stability of the leather marking system was enhanced. Marking trials were conducted in crust leathers, and the light fastness of these labeled crusts were tested. The results indicate that encapsulated DNA-hydroxyapatite-particles are more stable at sunlight radiation than non-encapsulated DNA. These marking trials showed that the system could be a suitable leather marking system in the leather industry to establish a powerful supplier and batch tracing.
 
 
Diagnosis, Prevention and Treatment of Fatty Spew 
by Ricardo A. Tournier
Volume: 110      Number: 8     Page: 260-276     Year: 2015
A comprehensive review of the possible causes and mechanisms of fatty spew formation is presented, together with a guide to remedial treatments for the defect. Best practices and trouble-shooting guidelines are provided that can be used for the prevention and systematic treatment of fatty spew on the tannery floor. The free fatty acid content of individual leathers can be used for routine assessment of the risk of spew events occurring at any stage of production, as well as the likelihood of fatty spew forming in crust and finished leather. A systematic approach to grading leathers according to their free fatty acid content is presented. This method can be applied on a routine basis in a production line, and/or prior to sending customer shipments.
 
 
Sustainability - Our Passport to the Future 
by Dietrich Tegtmeyer
Volume: 110      Number: 8     Page: 240-250     Year: 2015
This presentation will give an overview and a clear understanding of global sustainability as well as the urgent need and the importance of necessary paradigm changes in all kind of human life. In the last 100 years the economy was driven by growth and innovation optimism. Inventers and researchers, of course, did not know where all the developments finally will end up. However, the playground was so big and discoveries have been so interesting and fascinating that the developments process was self-running and could not be stopped or redirected. An extrapolation of this process will sooner or later end up being mortal because necessary resources are not available anymore to feed such a process. We are now fully arrived in the 21 century. The world today is already very much different than the one from the recent past 20 or even 50 years ago. We have generated for many people overwhelming prosperity in many countries which no one even dreamed about 100 years ago. The industrialization and joint fast growing global population has led to a point that the human race occupies nearly all livable land on this planet and utilizes resources to the last tiny corner of earth. A big mistake was that consequences for health and environment unfortunately have not been in the focus for a long period of time. If we and our next generations still want to enjoy life on our planet, a huge process of change is ahead of us. Never ever before in history have humans faced such an awesome task. I will review the evolution process of the megatrend sustainability from its beginning up to its mindset of today; what have been enablers, what – unfortunately – preventers during the industrialization process of the past 150 years, and what have been major milestones on the path to our current understanding of sustainable development. Based on this I will point out important challenges for our planet and our life. I will review guiding principles and rules, which have been identified as being required for necessary paradigm shifts in all levels of our day-to-day life: from a global economic and political point of view, from a company perspective as well as for each of us as an individual. In conclusion, I will briefly give my view on the positioning of the leather industry and comment on key items I believe our industry has to focus on.
 
 
Impact of Typical Surfactants on the Collagenolytic and Elastinolytic Activities of Proteases 
by Yanhong Li, Fenfxiang Luo, Biyu Peng and Bingbin Xu
Volume: 110      Number: 7     Page: 227-237     Year: 2015
Most proteases exhibit broad-spectrum activities to all of the protein components of skins, thus, the indiscriminate application of proteases will bring out undue and non-selective loss of skin structural proteins, especially collagen and elastin, and lead to loose and damaged grain. Finding the effective ways to control proteases’ activities against collagen and elastin in leather processes is very important. In this work, the influence of typical surfactants on the collagenolytic and elastinolytic activities of frequently used proteases was investigated, and the mechanism was also discussed. The results indicated that the nonionic surfactants had slight effects and anionic surfactants exhibited quite different behaviors on the collagenolytic and elastinolytic activities of selected proteases. Both collagenolytic and elastinolytic activities of trypsin preparations were obviously inhibited by all selected anionic surfactants, especially SDS and SDBS. For the bacteria proteases, their elastinolytic activities were significantly activated and their collagenolytic activities were inhibited to a variable extent by anionic surfactants. Tanners may effectively control the selective action of proteases to collagen and elastin to achieve different requirements through correctly utilizing surfactants.
 
 
Suitability of Different Oils for Chamois Leather Manufacture 
by K. Sandhya, N. Vedaraman, V. Sundar, R. Mohan, K. Velappan and C. Muralidharan
Volume: 110      Number: 7     Page: 221-226     Year: 2015
Chamois leather, conventionally made using fish oil finds wide industrial application. The major advantage with fish oils is that they contain significant amount of pentadienoic fatty acid in addition to higher iodine value. But the main problem with fish oil is its strong odor and high cost. The objective of the present work is to study the suitability of oils such as linseed oil, castor oil, sunflower oil, animal tallow for chamois leather manufacture in comparision with fish oil. The chamois leather, thus obtained was tested for properties such as sink test, water absorption and strength characteristics. Experimental results show that among different oils, linseed oil based chamois leather posseses higher water absorption and strength properties. It also has mild odour. This study shows that acceptable quality chamois leather can be made using linseed oil as tanning agent instead of fish oil.
 
 
Molecular Identification of Moderately Halophilic Bacteria and Extremely Halophilic Archaea Isolated from Salted Sheep Skins Containing Red and Yellow Discolorations 
by C. Akpolat, A. Ventosa, M. Birbir, C. Sanchez-Porro and P. Caglayan
Volume: 110      Number: 7     Page: 211-226     Year: 2015
Salted hides or skins containing red and yellow discolorations have been examined for many years, but much less information is available about the isolation and molecular techniques for identifying moderately halophilic bacteria and extremely halophilic archaea on the salted sheep skins exhibiting these blotches. The deteriorated salted sheep skins were collected from a warehouse in Spain. Moderately halophilic bacteria and extremely halophilic archaea were isolated from these samples and molecular identification of these microorganisms were performed using 16S rRNA gene sequence analysis. Total cell counts of moderately halophilic bacteria and extremely halophilic archaea were found as 105-108 CFU/g and 105-107 CFU/g, respectively. According to comparative partial 16S rRNA gene sequence analysis, Alkalibacillus halophilus, Pseudomonas halophila, Acinetobacter johnsonii, Alkalibacillus salilacus, Salimicrobium salexigens, Marinococcus luteus and Staphylococcus equorum subsp. equorum belonging to moderately halophilic bacteria; and Halorubrum tebenquichense, Halorubrum saccharovorum, Halococcus dombrowskii, Halococcus qingdaonensis, Natrinema pellirubrum, Halococcus morrhuae, Halorubrum kocurii, Halorubrum terrestre, Halorubrum lipolyticum, Halostagnicola larsenii, Haloterrigena saccharevitans and Natrinema versiforme belonging to extremely halophilic archaea were isolated from these sheep skins. Alkalibacillus halophilus belonging to moderately halophilic bacteria and Halorubrum tebenquichense belonging to extremely halophilic archaea were found as the most common species on the skins. Among the moderately halophilic bacterial isolates, Acinetobacter johnsonii showed lipolytic activities. Among the extremely halophilic archaeal isolates, Halococcus dombrowskii, Halococcus morrhuae, Natrinema pellirubrum, Halorubrum lipolyticum showed proteolytic activity and Halococcus dombrowskii, Halorubrum lipolyticum, Haloterrigena saccharevitans, Natrinema versiforme showed lipolytic activity. Hair slip, red and yellow discolorations, slimy layers and bad odor were detected on the skin samples examined. This study confirmed that salted sheep skins were contaminated by preservation salt containing different proteolytic or lipolytic species of mostly extremely halophilic archaea. Therefore, antimicrobial applications during brine curing of skins should be applied to overcome halophilic microbial damage on the salted skins.
 
 
Determination of Soluble Hexavalent Chromium in Dyed Consumer Goods Improvised by a Simple On-line Color Removal 
by R. Ganeshjeevan, S. Suresh, C. Muralidharan, S. Raja and A. Mandal
Volume: 110      Number: 7     Page: 204-210     Year: 2015
Hexavalent chromium detection in consumer articles is a statutory requirement and screening it in dyes and dyed leather is a challenge. Although many new improvised procedures were put forward, the lack of simplicity and automation leaves the void. The present study addresses these issues and offers a procedure that is closer to automated approach leading to finding that without the requirement of any special device the regular liquid chromatographic instrument can support a quick, simple and efficient method for hexavalent chromium detection in strongly colored leathers. The method was found to be effective in the removal of wide range of dyes and serving the detection of hexavalent chromium in ppb levels with %RSD of max. 3.5.