Leather Processing Research Articles

Valorisation of Basa (Pangasianodon hypophthalmus) Skin Waste into Quality Leather Using a Non Chrome Treatment Method

ABSTRACT Basa, a widely cultured, processed, and traded fish generates huge quantity of unutilized waste especially skin from processing units. Fresh cleaned Basa skin was treated with calcium carbonate (CCT), sodium hydroxide (SHT) and then treated with isopropyl alcohol and glycerin at three different ratios (0.5:1 (C1), 1:1 (C2) and 1:0.5 (C3)) at 4, 7, 14, and 30 days, respectively. Proximate composition, collagen and hydroxyproline contents of skin waste along with textural properties and histological analysis of developed fish leather were examined. The major constituent of skin protein was the collagen (43.31 ± 3.78%), which plays a significant role in leather processing. Histological analysis indicated that arrangement of collagen fibers before and after the treatment process demonstrated the adequacy of the process. The physical quality parameters such as tear strength (72.42 ± 0.22 N/mm) obtained for C3 at 14th day and tensile strength (67.65 ± 0.07 kgf) for C2 on the 7th day were found to be in acceptable range and comparable to animal leather. Value added leather products developed under the study had better acceptability. The technology and process developed will be a boost to the growing fish waste management problem around the world and a promising alternative for exotic animal leathers.

The Use of Sulfonated Jatropha curcas Oil for the Processing of Mechanically Improved Leather

Fatliquors are oil-in-water emulsions added during the fatliquoring process of leather manufacture to lubricate and prevent the fibre structure resticking during drying. They also increase softness, flexibility, and tensile strength of fixed leather. In this study, Jatropha curcas oil of no commercial value in Nigeria was sulfonated. The physicochemical properties of both the sulfonated and unsulfonated oils were determined. The sulfonated and unsulfonated oils were also characterized using DSC, FT-IR, 1H NMR, 13C NMR, and 13C NMR DEPT. The prepared sulfonated J. curcas oil was applied onto goatskin and compared with commercial sulphated fatliquor in the processing of shoe upper leather. Physical/mechanical analyses were carried out on fixed leather. Tensile strength, Sudan stain, elongation at break, and double edge tear test results showed notable improvement in the mechanical properties of the leather processed with the sulfonated J. curcas oil. The microscopic analysis also showed fibre structures that were adequately opened up. This study revealed that the sulfonated J. curcas oil can be a good sustainable substitute for commercially available fatliquor as its application in the processing of shoe upper leather shows properties that are comparable with the renowned fatliquors which are normally utilized in leather industries. It also raises the possibility of commercialization.

Nano-biocatalyst: Bi-functionalization of protease and amylase on copper oxide nanoparticles

There are reports that co-immobilization of enzymes on solid supports can circumvent the problem of loss of enzyme activity in a soup of enzymes. To understand the mechanistic pattern by which solid support can ensure enzyme stability. Copper oxide nanoparticles (CuO Nps) were employed to immobilize protease and amylase. These are enzymes widely used together and at different stages in various industrial activities such as laundry, leather processing, etc., the immobilization of enzymes was confirmed through FTIR, TGA, and zeta potential analysis. Enzyme activity assays were carried out to understand enzyme activity with and without immobilization. The interaction between the nanoparticle surface and enzyme was studied through molecular docking studies. Thus, the study provides an insight into how the immobilization of enzymes on nanoparticles could be beneficial for industrial applications.

Studies on Collagen Structure using X-Ray Scattering on a Closed-Loop Leather Process

Waste management in leather processing is crucial in limiting the excess use of hazardous materials that lead to environmental pollution and health concerns. A closed-loop approach was developed to recycle the spent solutions from leather processing to reduce waste in the effluent. The structural changes of collagen that accompany such processing are yet to be studied and is crucial in understanding the closed-loop process and its subsequent leather properties. In this study, we analysed the collagen structure at different processing stages across the closed-loop approach using synchrotron small-angle X-ray scattering. An increased filling effect in the collagen matrix was observed and attributed to the residual organic component and chromium species in recycled spent solutions. A high uptake of chromium was also observed from the increased scattering intensity from leathers treated with recycled chrome solution, indicating its efficient use. Additionally, the changes in scattering intensity from keratin and lipids indicated an effective unhairing process. Such findings on collagen structure changes will support the development of more environmentally and economically sustainable processing methods to benefit the leather industry.

Engineering a sustainable chrome-free leather processing based on novel lightfast wet-white tanning system towards eco-leather manufacture

Wet-white tanning system for chrome-free leather processing has been deemed as a feasible alternative from the source to effectively eliminate potential environmental and human health risks of conventional chrome tanning. This work presents a novel sustainable chrome-free leather processing based on lightfast wet-white tanning system of hydrolysable Tara tannins synergized with synthetic clay nanoplatelets (Laponite) and active aluminium salts (Lutan@ BN). The results show that the introduction of BN can significantly enhance the hydrothermal stability of wet-white leathers. The novel wet-white tanning system selected as 10% Tara–1% Laponite–3% BN for 2 h can endow the wet-white leathers with a shrinkage temperature (Ts) above 95 °C. Moreover, Tara–Laponite–BN complexes can be in-situ formed on the surface of the collagen fibers or between collagen fibrils within the collagen fiber strands, stabilizing primary and conformational structures of the collagens. Notably, the incorporation of BN within the collagens can increase the isoelectric point (IEP) of the leather matrix and facilitate exhaustions of anionic post-tanning chemicals in chrome-free leather processing. The resultant leather exhibits pleasant pastel color, favorable light-fastness, and reasonable physical performances without containing restricted hazardous Cr(VI) and free formaldehyde in accordance with current Chinese standard requirements for furniture leather and European Union Eco-label criteria. These results will provide more perspectives for designing and rationalizing sustainable chrome-free leather processing towards eco-leather manufacture.

Кожевенное производство в средневековом городе: опыт атрибуции

Кожевенное производство в средневековом городе: опыт атрибуции

Augmentation of protease production from psychrotrophic Acinetobacter sp. IHB B 5011(MN12) from Western Himalayas

Microbial proteases are explored for their role in food, detergent, bioremediation, pharmaceuticals, silk degumming and leather processing. Here, Acinetobacter sp. IHB B 5011 previously isolated from Western Himalayas was explored for optimization of protease production. A total of seven culture media; Basic medium (BM), Nutrient broth (NB), Gelatin broth (GB), Tryptone dextrose broth (TDB), Peptone Dextrose Broth (PDB), and Glucose Yeast extract Broth (GYB) were used. The maximum protease activity was recorded in PDB medium after 36 h. Different parameters including carbon and nitrogen source, inoculum and CaCl2 were evaluated based on Plackett-Burman design for optimum yield. The response for protease activity varied from 215-436 μg min-1 ml-1. Further, optimization based on Central Composite Design revealed protease production with 1.4 g dextrose, 0.7 g tryptone and 0.7 g yeast extract per 50 ml medium. A significant increase in protease activity was monitored from 323 μg min-1 ml-1 to 562 μg min-1 ml-1 after optimization.

Sistem Pendukung Keputusan Menggunakan Metode Analytical Hierarchy Process (AHP) dalam Penentuan Kualitas Kulit Sapi dalam Produksi Kebutuhan Rumah Tangga

Cowhide is the outermost part of beef that can be used in the product process, namely the finished skin in the production of household needs. The purpose of this study is to provide convenience in determining the quality of cowhide in household production needs. The data processed in this study were 6 alternatives. Cowhide quality data obtained at the UPDT Leather Processing Padang Panjang. There are several types of cowhide which have good, medium and poor quality levels. Furthermore, the data is processed manually using the Analytical Hierarchy Process method and continued by using the super software decisions as testing. The processing stage is to determine the weight of each criterion, provide an assessment (pair-wire comparation), summarize all the results of the assessment (overall composite weight). The results of the data processing are continued by calculating the level of accuracy. The result of the test on this method is that 98% of the cowhide has quality with vegetable cowhide based on the quality level of the given criteria. The testing decision making system has been able to identify the specific quality of cowhide. Through the Analytical Hierarchy Process method, the level of accuracy can be quite accurate and can help producers improve accuracy in identifying the quality of cowhide in household production needs.

Effect of cutting edge drying technology on the physicochemical and bioactive components of mango (Langra variety) leather

Mango ( Mangifera indica ) leather has been mostly known as a popular traditional snack of India. Though in recent days contemporary processing methodologies like hot air drying, microwave drying and freeze-drying are replacing the traditional approach (sun drying) of mango leather preparation. This study makes a unique combination of traditional ways of processing and modern technologies. Freeze dried sample with 2.19% protein and 78.30% carbohydrate content was found superior over all other differently dried samples. Different drying techniques significantly affect the moisture content of the final product, freeze dried sample has been found with the lowest moisture content of 16.31% while the same was observed maximum in sun dried sample (17.22%). Freeze-dried product has been found to be significantly (p < 0.05) different and nutritionally better from all the other products. Freeze dried sample was found best in terms of total phenolic content or TPC (7.2 mg/g db), total flavonoid content or TFC (3.27 mg/g db ) and total carotenoids content (205.1 μg/g db ) . Whereas, minimum TPC of 4.1 mg/g db and TFC of 4.1 mg/g db was observed for sun-dried mango leather. Hot air dried sample has been found with the lowest carotenoid content of 102.5 μg/g. In terms of DPPH, FRAP and ABTS antioxidant activity freeze dried sample has been found superior over hot air, microwave and sun dried samples. Maximum hardness (3.81 N) was observed for sun dried product while the same for lowest was 1.56 N for hot air dried sample. Hierarchical Cluster Analysis (HCA) shows the sun-dried, microwave and hot air-dried mango leather share the same cluster whereas freeze-dried mango leather has been placed in a different cluster depending on physicochemical properties studied. • Traditional and modern age drying techniques for mango leather processing. • In-vitro antioxidant activities. • Physico-chemical analysis of mango leather.

Application of boric acid doses in association with tannery sludge in the early development of black pepper

Information on the effects of boron and tannery sludge application on the growth and development of black pepper is insufficient to support the recommendations of these inputs for the crop. The present experiment estab­lishes adequate doses of boric acid in combination with the application of industrial waste from leather processing plants for the development of the black pepper cultivar ‘Bragantina’. We conducted the experiment in a green­house at IFES - Itapina Campus, Colatina city, Espírito Santo State, Brazil. For that, we used B horizon samples of a Red- -Yellow Argisol as substrate. The experimental design was completely randomized in a factorial scheme with four replicates. Treatments consisted of three boric acid doses (0; 2; 4 mg dm -3 ) in association with three tannery sludge doses (0; 0.125; 0.250 dm 3 dm -3 ) up to the vessel volume (18 dm -3 ), with 14 sampling times. We assessed the following variables: vegetative plant growth; symptoms of boron deficiency and/or toxicity; soil pH; boron content. Soil application of boric acid showed considerable results in the early development of black pepper plants; the dose with the best response was 2 mg dm -3 . Using tannery sludge doses of 0.125 and 0.250 dm 3 dm -3 in the substrate was lethal for black pepper.

OPTIMASI PENJADWALAN PRODUKSI MENGGUNAKAN PENDEKATAN ALGORITMA HARMONY SEARCH DI PT ADI SATRIA ABADI (ASA

PT Adi Satria Abadi (ASA) is a company engaged in the processing of leather, especially sheep skin and goat skin, which is used for the manufacture of golf gloves. The problem faced by the company is the production process that exceeds the due date to other customers who order products at PT ASA. From the research, it is known that the cause is a company scheduling method that has not been organized so that the production sequence is concurrent. Selection of methods Harmony Search algorithms in scheduling are caused by delays. The Harmony Search algorithm can provide a better makespan value than the company method. The results of the company method obtain 0.9 months makespan average, the Harmony Search Algorithm method produces an average 0.8 months makespan. In addition, the use of the Harmony Search Algorithm method can reduce the average value of 0.1 months makespan. The results of the study in three months experienced time savings of 0.6 months, 0.6 months and 0.1 months respectively.

The effects of non-metallic organic tanning agents on the microbial community structure in wastewater

Non-metallic organic tanning agents were used during the leather processing, most of them will be combined with the collagen converted it into leather. But there still some of its components were discarded into the wastewater and caused serious environmental problems. In this study, the structure character of microbial communities in leather wastewater containing non-metallic organic tanning agents and the effect of the leather wastewater on the ecology of the microorganisms were studied with the high-throughput sequencing. The results show that the presence of 1,657, 49 bacterial and fungal OTUs (Operational Taxonomic Unit), at 97% similarity level. Significant differences on microbial community composition in wastewater were observed in systems containing different non-metallic organic tanning agents. The Firmicutes and proteobacteria were dominated bacteria in T1, T3, T8, KB and T6. Ascomycota and Basidiomycota were the most richness fungi in T1, T3, T6, T8 and KB. The relative abundance of dominant bacteria pseudodomonas was significantly positively correlated with TN, NH3, and TOC (0.01 < P ≤ 0.05). The relative abundance of dominant bacteria Terrisporobacter and Ruminococcus_1 was positively correlated with pH (0.01 < P ≤ 0.05). The relative abundance of the dominant bacteria norank_o_JG30_KF_CM45 was positively correlated with TP (0.001 < P ≤ 0.01). The relative abundance of dominant bacteria Acidocella and Mycobacterium was significantly positively correlated with NO3 (P ≤ 0.001). In contrast, the relative abundance of norank_f_Elev_16S_1332 was negatively correlated with TN (0.01 < P ≤ 0.05). The relative abundance of norank_o_JG30_KF_CM45 was negatively correlated with NH3 (0.01 < P ≤ 0.05) and TOC (0.001 < P ≤ 0.01). The relative abundance of pseudomonas was negatively correlated with pH and TP (0.01 < P ≤ 0.05). Pseudomonas, Clostridium, Turicibacter, Acidocella, Intestinibacter, and Bacillus are highly tolerant bacteria in non-metallic organic tanning agents wastewater. These highly tolerant microorganisms should be actively explored for bioremediation of non-metallic organic tanning agents wastewater.

A Rapid Method for Measuring Elastin Degradation and Its Application in Leather Manufacturing

The degradation of elastin in skins during leather manufacturing can increase the yield area, softness and flatness of the leather, but, excessive degradation of elastin in leather processing induces looseness and increases veininess in the final leather product. However, the characterization of the degradation degree of elastin in skins and leathers was mostly studied through histological analysis qualitatively. There is an urgent need to develop a more efficient quantitative analytical strategy to evaluate the degradation of elastin in leather making processes. In this study, a simple and rapid HPLC method is developed for measuring elastin degradation in skins, leathers and leather processing liquors through determining the biological markers of elastin, namely desmosines. The separation of analytes was conducted on an C18 column (4.6 × 150 mm, 4.0 ?m) at 30 ?; the wavelength of diode array detector (DAD) was set at 275 nm; the mobile phases were composed of methanol and aqueous acetic acid (2.0 %, v/v). A gradient elution was carried out at a flow rate of 0.5 mL/min. It has been witnessed that Cr (III) has no effect on the retention time and peak area of desmosines, when the concentration of Cr (III) was in the range of 0 to 200 mg/L. In quantitative analysis, all of the calibration curves showed good linear regression (R2 ? 0.9990) within the tested ranges, and the recovery of desmosines was 100.9 % and 102.6 % for elastin hydrolysate and Cr-tanned elastin hydrolysate, respectively. The content of desmosines in elastin fiber, Cr-tanned elastin fiber and leather manufacturing liquors measured by established HPLC-DAD were comparable to the results obtained by amino acid analyzer. In the wet blue bating process, the quantitative analysis results are consistent with the histological staining results. The results demonstrate that the developed method is accurate and effective and can be readily utilized for the comprehensive process control of leather manufacturing.

The Structural and Chemical Properties of the Nile Perch Fish Leather

The conversion of skin to leather involves structural, chemical and physical changes to the material. The changes to the material is often after every subsequent process that the skin goes through before getting to the final leather. The leather processing involves three sub stages; pretanning, tanning and post tanning. The aim of the study was to determine the structural and chemical properties of chrome tanned Nile perch fish leather. The structural properties were determined using scanning electron microscope (SEM). The materials were analyzed for both the surface and cross section. The structural properties were carried out on the raw material then the material was subjected to tanning and there after the structural properties were determined in order to note the change that the tanning has on the structural properties of this particular material. Chrome content was analyzed using atomic absorption spectrometer (AAS) and amount was reported in percentage content. The moisture content was quantified and reported in percentage value.&#x0D; From the structural analysis it was noted that the raw material is less compacted as compared to the chrome tanned leather. The fibers of the materials runs in one direction. The speed of the drum needs to be regulated to reduce the destruction of the collagen fibers which largely affects the physical properties of the leather. The average values of chemical properties were reported as follows: Chrome content of 2.45 % and Moisture content of 13.33 ± 1.88 % .The chrome content that was offered in the leather was satisfactory to give it a good hydrothermal stability.

Export Trend of the Leather Industry of Bangladesh: Challenges to Sustainable Development

Purpose: The principal objectives of the study are to find out the contribution scenario of the leather sector towards the economic development of Bangladesh and to know the background of the leather industry, export performance, item wise contribution, country-wise export trend and contribution in GDP. Methodology: The present study is a descriptive one and based on mainly secondary information. The data was collected from various journals, research articles, thesis papers, newspapers, online news, survey reports, and annual reports and files. In this study, a descriptive technique was adopted in tabular form, column chart, line chart, pie chart, bar chart to analyze the results and represent collected data and information. Findings: The leather sector of Bangladesh is the second-largest export earners after the ready-made garments sector. This sector contributes enormously to the socio-economic development of Bangladesh. The research findings reveal that the export contribution of leather was 8.14% in FY 1990-91, but after that, the contribution of leather sector is decreasing, one of the main reasons is the export trade had been singlehandedly driven by the RMG sector, now its share is almost 2.52% ($1.01billion) of the export earnings. The study shows that the export earnings from leather footwear were 60% growth rate in FY 2018-19 due to riding the trend of increased leather footwear exports in the United States, whereas, the contribution of processed leather and leather products is 24% and 16% respectively. The study also reveals that the leather sector is contributing significantly to the GDP. Leather items are exported from Bangladesh to about 53 countries of the world. The leather sector is also a major employer of semi-skilled or unskilled workers, directly employs around 200,000 people and around 850,000 are connected to the sector indirectly. Limitations: I faced some difficulties for collecting data. Moreover, the study could not deliberate the reflection of statistical tools for analysis of the data. Practical Implications: The export earnings from the leather industry were in good shape before the inception of tannery relocation. But the tanneries are suffering from 2017 as the relocation hit the production of leather processing because some tanneries are not yet in operation. For improving the export performance, the study will be helpful for stakeholders, industry owners, and management, BTA, BFLLGFEA, LFMEAB and buyer’s association. Originality/Value: The study findings clearly showed and explained the comparative position of the export trend among processed leather, leather footwear and leather goods.

Chemical/Water-Free Deliming Process Using Supercritical Carbon Dioxide: A Step toward Greener Leather Manufacture

Sustainable management plays a vital role in the emerging world, reproducing a pollution-free environment and leading to sustainable growth. In that aspect, leather industries are cornered toward greener leather processes to reduce chemical and water usage. On the same path, deliming is one of the significant steps in the pretanning process to drive into a greener process because the conventional deliming process requires 4% ammonium salts and 100% water, which leads to an enormous amount of ammonium salts in wastewater, leading to eutrophication which adds to the pollution load. To reduce the pollution load, in this work a chemical and water-free deliming process is performed using supercritical carbon dioxide (SCCO₂) as a medium as well as deliming agent to remove the lime content from goat skin at 75 bar pressure within 10 min. Also, the utilized CO₂ is collected and reused for the subsequent set of processes. The morphological analysis shows no grain damage on delimed pelts processed using SCCO₂, and leathers post-tanned from this system exhibit better organoleptic and mechanical strength properties. The developed process opens newer vistas for sustainable development in leather manufacture.

A smart high chrome exhaustion and chrome-less tanning system based on chromium (III)-loaded nanoparticles for cleaner leather processing

Currently, chromium-containing wastewater from tanning process has seriously restricted the sustainable development of the leather industry. This problem can be solved by high-exhaustion chrome tanning technology and chrome-less tanning technology. However, these techniques not only fail to achieve a uniform tanning effect but also reduce the performance of the leather. In this work, pH-sensitive and chromium (III)-loaded nanoparticles were fabricated by self-assembly of poly [poly (ethylene glycol) methyl ether acrylate-co-acrylic acid-co-glycidyl methacrylate (PEGMA-co-AA-co-GMA)] terpolymers templated Cr(OH)3 mineralization, which were defined as Cr-PPAG NPs and utilized as smart high chrome exhaustion and chrome-less tanning agents. Due to the core-shell structure, these Cr-PPAG NPs exhibit a ‘Trojan horses’ behavior which can protect Cr3+ from reacting with skin collagen during the penetration process, leading to effective and uniform delivery of Cr3+ to the rawhide’s interior. Then, the released Cr3+ from Cr-PPAG NPs could cross-link the carboxyl groups both on the skin collagen and poly (PEGMA-co-AA-co-GMA), thereby producing the high-exhaustion chrome tanning effect. Furthermore, the GMA moieties of poly (PEGMA-co-AA-co-GMA) could further react with amino groups of collagen fiber. The synergy between chrome tanning and the organic tanning effects provided by Cr-PPAG NPs resulted in a chrome-less tanning technology. Finally, the final leather tanned with Cr-PPAG NPs exhibiting improved hygienic characteristics with excellent antiadhesive properties against E. coli and S. aureus bacterial strains.

Assessment of Hexavalent Chromium Pollution in Buriganga and Dhaleshwari River Waterbodies Adjacent to Tannery Estates in Bangladesh

Recently, in Bangladesh, all tannery industries have been relocated to a new location exclusively established for leather processing industries with modern manufacturing facilities and effluent treatment plants with standard probations. Effluents generated from the tannery industries are now being disposed of into the surrounding river water bodies. In this study, our goal was to investigate the presence of chemical contaminants like hexavalent chromium (Cr6+) in the water bodies surrounding tannery industries and to understand the possible role played by the tannery effluents in contaminating the river water bodies with Cr6+. Result analysis revealed the presence of an amount of Cr6+ (ranging from 0.01 mg/L to 3.54 mg/L) in the surrounding water bodies, which was far above the maximum permissible limit of Cr6+ (0.05 mg/L for surface water), set by the Environmental Protection Agency. It is, therefore, plausible to assume that effluents from the tanneries play an important role in hexavalent chromium contamination of water bodies surrounding tannery industries.

Production and characterization of a novel thermo- and detergent stable keratinase from Bacillus sp. NKSP-7 with perceptible applications in leather processing and laundry industries

Keratinase has the ability to degrade the recalcitrant keratinous wastes that cannot be degraded by conventional proteases. The present study describes a novel hyperstable keratinolytic enzyme from Bacillus sp. NKSP-7, which has excellent efficiency of keratin-feather biodegradation, washing and dehairing. The production of extracellular keratinase was improved by 3.02-fold through optimization of various parameters. Purified keratinase (25 kDa) showed optimal activity at 65 °C and pH 7.5, and displayed stability over a range of pH (5.5–9.5) and temperature (20–60 °C) for 8 h. No conspicuous effect was perceived with various chemicals and organic solvents, however, the catalytic efficiency was enhanced in the presence of Ca2+, Cd2+, Na+, Mn2+, sodium sulfite, and β-mercaptoethanol. The enzyme was completely inhibited by phenylmethanesulfonyl fluoride (PMSF), suggesting that this keratinase belongs to serine protease family. It displayed prodigious stability and compatibility to salinity and commercial detergents. Enzyme exhibited great substrate specificity but high affinity was observed with keratin-rich substrates. Crude and purified keratinase revealed perceptible potential for destaining of blood-stained fabric (10 min), and dehairing of hide (8 h) without any damage. All these auspicious features make this enzyme a promising candidate for various industrial applications, especially in keratin-waste management, detergent formulations and leather processing.

Innovative Technologies for Рrocessing Leather and Fur Raw Materials

The innovative developments in the field of processing of leather and sheepskin-fur coat raw materials are presented. New technologies make it possible to process sheepskin and leather raw materials with a minimum consumption of chemical materials, consume fresh water, generate wastewater and shorten the processing.