Tanning Process Research Articles

Effect of leather tanning process on stable isotopes and radiocarbon in tissues of Persian leopard: Preliminary results

Effect of leather tanning process on stable isotopes and radiocarbon in tissues of Persian leopard: Preliminary results

Comprehensive Method for Supplier Selection in the Indonesian Leather Industry Considering Sustainable Development Goals Criteria

Objective: This pivotal research aims to rank raw material suppliers at an Indonesian leather company using the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). It is based on Sustainable Development Goals (SDGs) criteria selected by many decision-makers through the Delphi method, with a compromise criteria weight between Methods based on Removal Effects of Criteria (MEREC) and Stepwise Weight Assessment Ratio Analysis (SWARA) II. Theoretical Framework: The global and national commitments of Sustainable Development Goals (SDGs) to improving society's welfare, including the sustainable use of resources, are not just theoretical concepts. They are practically applied in this research to guide supplier selection in the leather industry. These criteria are then weighted using objective weighting (MEREC) and subjective weighting (SWARA) II, and the results are compromised to form the basis for evaluating suppliers using TOPSIS. Method: The proposed method in this research consists of three stages. The first stage is selecting the SDGs criteria using the Delphi method, a structured communication technique involving experts. The second stage is weighting the criteria using MEREC for objective weighting and SWARA II for subjective weighting. The third stage is supplier evaluation using TOPSIS based on the weight of the compromised criteria. Results and Discussion: The ranking of leather raw material suppliers for Indonesian leather companies is Kediri, Rembang, Jombang, Cirebon, Wonogiri, Lumajang, Cianjur, and Sidoarjo. This ranking is based on the SDGs criteria. Responsible leather sourcing, eco-friendly tanning processes, water use audits, and waste management are the SDGs' criteria for selecting suppliers in the Indonesian leather industry. Responsible leather sourcing is the only sustainability criterion more important than the price criterion. This criterion directly affects the quality of the animal skin, which is why it is rejected. Research Implications: The manager should prioritize the SDGs criteria, such as the product's significance to the organization's survival over cost and other factors, which have become secondary due to high demand. Apart from rejecting and delivery factors, management also considers responsible leather sourcing. This means that good animal care impacts the reject factor, and management prioritizes this factor. The rejection criterion must be prioritized for the production process to operate efficiently. Originality/Value: It is imperative to establish a technique for managers in the Indonesian leather sector to choose sustainability suppliers incorporating Delphi, MEREC, SWARA II, and TOPSIS.

Occupational exposure assessment of heavy metals in human scalp hair among tannery workers in Bahir Dar, Ethiopia: Indication of pollution

Ethiopia, is one of the African countries, has immense potential for skins and hides for the leather industries, which will play a crucial role in converting nations into manufacturing-driven economies through industrialization. The chemicals applied in the tanning process are a serious concern for employees and the community if proper safety measures are not taken. The pollution status of employees working in Anbessa and Bahir Dar tannery factories was evaluated by collecting hair samples. After the hair samples washed with acetone, and deionized water, the hair samples were digested with 4 mL of HNO3 and 2 mL of HClO4 for 1:30 h at 250 °C. The levels of metals (Cr, Pb, Zn, Cu, Ni, and Cd) were subsequently analyzed using a Flame Atomic Absorption Spectrophotometer (FAAS). The mean concentrations of Cu, Ni, Zn, Pb, and Cr in the Anbessa tannery factory workers were 17.34–22.75, 16.38–35.03, 235.4–369.2, 30.46–67.31, and 97.56–189.18, respectively, in the various working departments of the factory. Similarly, the concentrations of Cu, Ni, Zn, Cd, Pb, and Cr in the hair of Bahir Dar tannery workers were 30.1–105.9, 17.88–62.20, 216.9–762.1, 0.35–5.21, 33.42–91.42, and 118.5–305.7, respectively. Chromium was found to be the most accumulated metal next to Zn with in both tannery workers that highlighted significant occupational health risks. The principal component analysis (PCA) analysis provide an insights into the interactions between occupational factors and metal exposure. In conclusion, the results of hair analysis from the employees of tannery factories indicates alarming levels of metal exposure, especially for zinc and chromium, which might pose health problems in long time exposure. Thus, it's critical to monitor occupational activities that can harm human health and the environment.

Ecological implications of chromium-contaminated effluents from Indian tanneries and their phytoremediation: a sustainable approach.

Industrial activities are paramount to sustaining the economy in a rapidly developing nation and global powerhouse like India. Leather industries are important in the country's economic map due to the high revenue and employment generation opportunities. Several of these industries contribute largely to environmental pollution. The pollution of the environment is mainly caused by improper disposal of the tannery effluents that are highly rich in hexavalent chromium, a potent human carcinogen. Hexavalent chromium imparts toxic effects on the biotic components, which include plants, animals, and humans. The review portrays the current status of the Indian leather tanning sector and its impact on the Indian economy. The process of chromium tanning and its adverse effects on the environmental biotic components have been briefly discussed. Phytoremediation of these effluents using suitable hyperaccumulating plants has been suggested as an eco-friendly and cost-effective approach for the sustainable restoration of the polluted environment. The mechanism behind the remediation approach and the factors influencing it have been detailed. The manuscript briefly discusses some important advancements in the field of phytoremediation and emerging technologies and concludes by emphasizing further research for sustainable management of tannery wastes.

Characteristic of Chrome-Tanned and Vegetable-Tanned Goat Garment Leathers

ABSTRACT. Chrome tanning material is still widely used in the tanning process for garment leather production. Its use began to be reduced to overcome its negative environment impact. Vegetable tannin of a mimosa and tara combination was used in this study to substitute chrome tanning material. Garment made from vegetable-tanned leather with a ratio mimosa to tara of 5:13 was compared to garments made from chrome-tanned leather, both the production methods and resulting leather characteristics. To obtain garment leather characteristics, chrome-tanned leather requires auxiliary materials and two fatliquoring steps. Vegetable-tanned leather requires more auxiliary materials and fatliquoring steps (3 steps). Physical test results show that chrome-tanned leather gives better tensile strength, elongation, tear strength, and softness that meet with SNI (Standar Nasional Indonesia or Indonesian National Standard). Meanwhile, garments from vegetable-tanned leather exhibit elongation, tear strength, and softness that meet with SNI. However, adding auxiliary materials and fatliquoring steps in the garment-making process from vegetable-tanned leather is still unable to produce the softness, smoothness, and elasticity of a garment from chrome-tanned leather.

Possible Remediation Approaches for Wastewater Containing Dyes; A Review

Abstract One of the most serious environmental problems is water scarcity and water pollution is a worldwide issue that can have an impact on people, plants, animals, and trees. Reusing wastewater makes sense in light of the limited availability of freshwater sources to conserve and expand the pool of available water sources. Numerous things can contaminate water supplies. Although the fundamental concepts are usually the same, the process of water restoration may vary from one location to another based on the source of contamination. Dyes are a versatile group of organic compounds found in many industries ranging from textiles, papermaking, leather tanning, and food processing. However, untreated or partially treated dye-containing wastewater in the environment can have a significant impact on human health and ecosystems. Dyes can color water bodies, making them aesthetically displeasing and inhibiting the penetration of sunlight. This may cause water plants and algae to produce less. While certain dyes are carcinogenic or mutagenic to humans, others are poisonous to aquatic life.

Devising a technology for obtaining glued sausage casings from intestinal raw materials using electrophoresis

The object of research is the technique for obtaining glued sausage casings, in which adhesive related structures and electrophoresis for tanning are used to glue the layers of intestinal raw materials. Devising a technique for gluing sausage casings from intestinal raw materials with the use of adhesive related structures by stitching by tanning, via intensified electrophoresis, has been substantiated. The technology of glued sausage casings from intestinal raw materials, which are classified as unclaimed residues and waste, has been proposed. The technology differs from known similar technologies by applying a technique for gluing intestinal membranes using an adhesive related construct and electrophoresis during tanning. The devised gluing technique and the device for its implementation make it possible to avoid violation of the integrity of the raw material, are universal in relation to it, and are easy to operate. The rational parameters of electrophoresis, which is used to accelerate the tanning process of the place of gluing of the layers of the intestinal membranes using an adhesive related construct, have been determined. The potential difference between the electrodes and the duration of exposure of the gluing site for gluing the original intestinal raw materials: pork belly, lamb belly, beef belly were determined. At a potential difference of 100 V, the duration of exposure of the gluing site for pork and lamb bellies is 17 minutes, and for beef bellies − 20 minutes. It is noted that the results differ in the duration of exposure of the gluing site, which is probably due to the thickness of the layer of the raw material. The proposed technology would contribute to improving the efficiency of the technology of glued sausage casings from intestinal raw materials and could be used at enterprises for the processing of agricultural products and the meat processing industry

Environmental performance of three innovative leather production processes using less chromium and water

Leather production contributes positively to economic developments but can create severe environmental impacts, due to the associated consumptions of water and chemicals. The substance of main concern is the basic chromium sulphate, widely used as tanning agent, which provides high-technical performance to the finished leather. This study quantifies the environmental sustainability of a conventional leather production process and those of three innovative processes, characterised by limited consumptions of chromium and water. Standardised life cycle assessments were implemented, with reference to the production chains starting from pickled skins until the production of two finished leathers (for goods and footwear), having the same technical and aesthetic characteristics of those from the conventional process. The innovative tanning processes adopt conventional rotating drums or substitute them with spray nozzles or aerosol rooms, and require a specific pre-treatment that includes de-pickling, drying and stabilisation of input skins. Tests at industrial scale (or at pilot scale for the solution with aerosol rooms) indicate that the new processes strongly reduce impacts in terms of Human toxicity-cancer, Ecotoxicity freshwater and Resource use-minerals and metals (up to 57 %, 29 % and 48 %, respectively) even though they imply an increase in terms of Climate Change (up to 51 %). Losses of chromium in wastewater and solid waste are reduced from >33 g/m2finished leather, for the conventional process, to about 8 g/m2finished leather, 5 g/m2finished leather, and 1 g/m2finished leather, for the innovative processes.The environmental sustainability of the proposed new processes increases from the solution with drums (and less water and chromium) to that utilising spray nozzles and aerosol rooms. A great improving can be obtained even just with the “simple” new drum solution, able to reduce the Human toxicity-cancer potential up to 53 % and Resource use-minerals and metals potential up to 42 %.

Discarded enoki mushroom root-derived multifunctional chrome-free chitosan-based tanning agent for eco-leathers manufacturing: Tanning-dyeing, non-acid soaking, and non-basifying

The aim of this study was to develop new discarded enoki mushroom root-derived multifunctional chrome-free chitosan-based tanning agents that can be used for eco-leather manufacturing. In this study, oligochitosan (OCS) was prepared from chitosan extracted from the enoki mushrooms and chemically modified using reactive dye R19 and epichlorohydrin (ECH) to prepare chromium-free tanning agent (OCS-R19-ECH) with both tanning and dyeing functions. FT-IR, XRD, and NMR (1H) confirmed the successful synthesis of the product. The molecular weight of OCS-R19-ECH is 6355 g/mol, with an average particle size of 1249.37 nm and an epoxy value of 0.276 mol/100 g. OCS-R19-ECH was used for tanning experiments on bated sheepskin, and the results showed that the leather tanned with OCS-R19-ECH not only exhibited excellent wet-heat stability (shrinkage temperature = 81 °C), but also superior dyeing uniformity, resistance to dry and wet abrasion, mechanical strength (tensile strength = 12.4 MPa, tear strength = 57.3 N/mm), and outstanding antimicrobial properties. Most importantly, compared with traditional tanning agents, OCS-R19-ECH has a higher pH (9.0), tanning-dyeing integration, non-acid soaking, and non-basifying can be achieved in leather making, which can greatly simplify the tanning processes. This new multifunctional chrome-free chitosan-based tanning agent facilitates high-value utilization of waste resources.

Experimental Study on the Removal of Toluene from Water by PTFE Hydrophobic Microporous Membrane Using Air Gap Membrane Distillation Process

Toluene is used for various purposes such as a cleansing agent, paint thinner, lacquers, printing, and leather tanning process. However, it has an adverse effect on human bodies, such as skin irritation, leukemia, respiratory issues, mutagenicity, etc, when the chemical gets mixed in drinking and rainwater by the above routes. Therefore, there is a threat to the environment and society because of the presence of toluene in water bodies through industrial effluent. Henceforth, in this study, toluene is separated from water using the air gap membrane distillation (AGMD) process. The hydrophobic microporous poly-tetra- fluoro-ethylene has been employed for this purpose. Primarily, this work focussed on the study of operating parameters such as feed solution temperature and coolant temperature on the AGMD performance namely permeate flux and toluene selectivity. It was observed that the permeate flux increased exponentially from 2.07 kg/m2h to 9.23 kg/m2h, and 0.94 kg/m2h to 3.53 kg/m2h. However, it was found that the permeate flux decreased from 9.48 kg/m2h to 8.12 kg/m2h, and 3.78 kg/m2h to 2.42 kg/m2h on increasing the coolant temperature from 5°C to 25°C at 3 mm and 11 mm air gap, respectively. The membrane selectivity was found to be less than 1, which signifies the efficient toluene-water separation. In order to study the membrane performance in the long run, the permeate flux was estimated continuously till 60 h wherein the estimated flux was found to be almost constant. The membrane morphology before and after the 60 h experimental run was analysed using capture FE-SEM micrographs. The toluene concentration was estimated using a spectrophotometer at a wavelength of 264 nm.

Ultrasound-Assisted Extraction, Characterization and Assessment of Vegetable Tannins from Guava (Psidium guajava) Leaves for Leather Tanning

For commercial leather processing, chrome tanning is the most used approach but it significantly contributes to environmental pollution. Vegetable tannins, which are large polyphenolic compounds, form strong interactions with proteins and carbohydrates, thereby enhancing the adaptability and value of vegetable-tanned leather as well as reducing environmental impact. In this study, vegetable tannins were extracted from the leaves of Guava plants (Psidium guajava) using ethanol as the solvent, facilitated by ultrasound. Extracted tannins were quantified using the Folin–Ciocâlteu reagent with ultraviolet-visible spectroscopic method. Ultrasound enhanced the extraction process producing a high yield in less time due to its mechanical, thermal, and cavitation impacts. The extracted tannins were characterized by a variety of spectroscopic techniques, including Proton (1H) Nuclear magnetic resonance, Fourier-transform infrared, and ultraviolet-visible spectroscopy. The effect of various process variables, such as temperature, solid-liquid ratio, ultrasonic power, extraction period, and powder fineness, were also investigated to optimize the extraction process. Finally, the extracted tannins were employed in leather tanning processes to assess their potential as tanning agents. The extracted tannins ensured uniform diffusion of tannins, improved thermal stability and reduced the number of tannins in effluent by 68% making it an environmentally friendly leather tanning process.

A New Synthesis Method and Characterization of Graphene Oxide Nanocomposites for the Leather Tanning Process

Environmental pollution caused by wastes generated from chrome tan is a major concern nowadays. This study aimed to develop an eco-friendly alternative tanning agent using graphene oxide (GO) based nanocomposite materials. GO was synthesized by a new approach with modification of the Hummers method. Two types of GO-based nanocomposites, GO-TiO2 (GT) and GO-TiO2-PEG (GTP) were prepared by adding TiO2 nanoparticles and polyethylene glycol (PEG) as surface modifiers. They were successfully applied to leather tanning processes at different concentrations (2%, 4%, and 6%). Both synthesized GO, GO-nanocomposites, and the resulting tanned leathers were characterized by Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA), and Fourier-transform Infrared Spectroscopy (FT-IR). Different physico-mechanical properties of leathers tanned with nanocomposites were evaluated and the results were compared with chrome-tanned leathers. The tensile strength of chrome-tanned leather was 223 (kg/cm) whereas the maximum tensile strength was found at 228 (kg/cm) and 233 (kg/cm) in 6% GO-TiO2 and GO-TiO2-PEG tanned leathers respectively. The environmental pollution impact of the effluents generated by the new tanning process was assessed. The COD of effluents generated from chrome tanning was 4800 ppm which was significantly reduced to 2400-1440 ppm and 2880-1920 ppm when GO-TiO2 (GT) and GO-TiO2-PEG (GTP) were applied in leather tanning respectively. The TDS and BOD were found at 183.8 and 200 ppm in conventional chrome-tanned wastewater which were significantly reduced to the range of 47.5-18.3 and 100-50 ppm respectively in liquid wastes obtained from the GO-composite tanning process. The maximum reduction of COD, BOD, TDS, and TSS in leather waste liquid was found with the application of 2% GO-nanocomposites in tanning. The results revealed that leathers tanned with nanocomposites possess characteristic properties which were very similar to those observed in chrome-tanned leathers whereas the new tanning agents drastically reduced the intensity of pollutants in leather effluents. The application of new nanocomposites in the leather tanning process is an innovative effort. This new nanocomposite-tanning method showed minimal consequences regarding environmental pollution with the generation of less toxic effluents from the respective tanning process.

Energy-saving and low-carbon leather production: AI-assisted chrome tanning process optimization

Reducing CO2 emissions is a global effort to improve industrial cost efficiency, enhance product compatibility, and fight climate change. For leather-making industry, the optimization of tanning process is crucial to fulfill the goal of low-carbon manufacturing. Artificial intelligence (AI) is an emerging technology for its ability to reduce errors, increase efficiency, and help realizing precise optimization of manufacturing processes. Herein, an AI-assisted method was first proposed to optimize chrome tanning process for energy-saving and carbon reduction. By comparing the performance of four machine learning (ML) algorithms, i.e., multiple linear regression (MLR), polynomial regression (PR), support vector regression (SVR), and backpropagation-artificial neural network (BP-ANN), it was found that machine learning models are superior in identifying the optimization of process parameters (pH and time) which lead to maintain key product quality indexes in the penetration procedure and binding procedure. Out of the four ML models, the BP-ANN algorithm and SVR algorithm are proven to have good predictive ability. Thus, we systematically optimized the chrome tanning process for energy saving, with key product quality as the constraints. The optimal process parameters, namely pickling pH of 2.86, penetration time of 90 min, pH after basifying of 4.08, and binding time of 90 min, were generated by solving the optimization models of the chrome tanning process via the genetic algorithm (GA) with powerful global optimization capability. Finally, it was validated that the optimized process was highly reliable by evaluating the wet blue product performances, such as the evenness of chrome distribution, thermal stability, surface reactivity, morphology, as well as physical and mechanical properties. Notably, compared to conventional chrome tanning, the optimized process will save 8353.33 kgce of energy and reduce 87295.6 kgCO2 of CO2 emission in an average tannery with an annual production capacity of 300,000 standard sheets of upper cowhide leather. This approach can precisely optimize conventional leather-making process, providing a fesible way to achieve energy-saving and low-carbon leather production.

Optimization of Tannin’s Extraction from Cashew (Anacardium occidentale L.) Nut Testa for Use in Leather Tanning

Extensive researches have been conducted over the years, focusing on the use of vegetable tannins to reduce pollution caused by mineral tanning. Vegetable tannins have been utilized commercially, but they remain costly and are not easily accessible. The purpose of this study was to optimize the tannin’s extraction from cashew (Anacardium occidentale L.) nut testa using water in order to determine their suitability in leather tanning. Samples of cashew nut testa were collected randomly from cashew nut processors in Mtwara region, Southern Tanzania. They were shade-dried and ground into powder. Various ratio of powder/water (1:6, 1:9, 1:12 and 1:15) -on weight basis were made for extraction, maintained at a temperature of 70 0C for 90 minutes. Results showed that, depending on the extract ratios, different tannin concentrations were obtained which had an implication on tannin extracted from powder. Experiment was found solution with ratio 1:9 have shown to extract about 50.73% of total tannins presented on cashew nut testa powder followed by solutions with ratio 1:12, ratio 1:15, and ratio 1:6 extracted about 46.27%, 43.51% and 38.95% respectively. Suitability of various tannins solution extracted from cashew nut testa was tested using conventional tanning process on sheepskins. The physical properties of the resultant leathers were determined using the standard methods (TBS/ISO). Under given condition, it has shown that using the ratios of 1:6, 1:9, 1:12 and 1:15 resulted in leather with tensile strength ranging between 19.41+6.36 MPa and 43.00+8.18 MPa and elongation at maximum load in the range of 34.48+10.12 % to 77.56+10.96 %., average shrinkage temperatures were above 75oC, and flexing test gave no damage of leather at 100,000 flexes. The physical properties of leather recorded have shown to meet the minimum recommended values from the standard (ISO 14931-2021). The mixing ratio 1:9 of cashew nut testa powder/water has been recommended for extracting tannin for vegetable tanning.

Waste management and salt recovery from solid residue of tannery common effluent treatment plant

ABSTRACT The considerable amount of solid residue generated by the common effluent treatment plant (CETP) of tanneries needs adequate treatment and reclamation before ending up in the environment as solid waste. A sustainable process aiming at tannery CETP waste minimisation and its reuse for sodium chloride salt recovery is presented. The integrated approach consists of dissolution, decolorisation, filtration, evaporation, and crystallization as unit operations. Lab-scale parametric studies have been undertaken to investigate the effects of various parameters at different process stages on product (sodium chloride) yield and quality. The developed process resulted in the recovery of 93% NaCl, having a purity of ∼98.5%. The optimised operating conditions were tested on a bench-scale system (15 kg batch scale of solid residue) deploying solar energy for evaporation-crystallization, and process feasibility was established. An economic analysis was performed, and the techno-economic feasibility was demonstrated to produce 15,733 tons per annum (TPA) of NaCl from 20,000 TPA of solid residue. The techno-economic analysis favours the treatment of tannery CETP waste with the method specified. The proposed scheme can tackle waste management and reuse the recovered product in the tanning process.

Tuning a green carboxymethyl cellulose-based pre-tanning agent via peroxide oxidation for high chrome exhaustion in leather industry

The low chrome uptake by collagen in the conventional tanning process leads to the pollution of the wastewater. Due to environmental concerns, leather scientists are already searching for innovative ways to produce pre-tanning agents as a high exhaustion chrome tanning auxiliary. Herein, a novel kind of pre-tanning agent is engineered by converting carboxymethyl cellulose (CMC) to oxidized carboxymethyl cellulose (OCMC) via the hydrogen peroxide process. FT-IR and carboxyl content analysis demonstrated the increase in carboxyl content after oxidation. After that, the obtained OCMC was utilized as a pre-tanning agent, resulting in a high exhaustion of chrome (92.76 %) which is 27.76 % more than conventional chrome tanning (65 %), and the amount of chrome in wastewater reduced to 7.24 %. The hydrothermal stability of wet-blue increased by increasing the uptake of chrome (Ts = 118 °C). The obtained crust leather represented excellent mechanical properties (Tensile strength: 305.68 kg/cm2; tear strength: 50 kg/cm) and desirable organoleptic properties. The environmental analysis signifies a significant step towards a cleaner and sustainable tanning process (COD = 1600, BOD5 = 560 mg/L) compared to the conventional chrome tanning process. Consequently, the obtained results offer a green pre-tanning agent to meet the requirements of the sustainable development of the leather industry.

An augmented reality approach for communicating intangible and architectural heritage through digital characters and scale models

Intangible cultural heritage (ICH) represents living cultural expressions and practices that are part of the heritage of a community, and their preservation and transmission are considered highly important. Various methods and tools have been applied so far for the digitization and dissemination of ICH content including a wide range of technologies. Mobile augmented reality is a promising solution along this path that enables the overlap of digital and real-world information in an engaging and efficient manner. Despite the widespread use of AR in cultural heritage, there are not many studies regarding the user experience, the learning outcomes, and the way in which users observe and interact with the virtual content. This paper presents a mobile augmented reality installation that re-enacts the stages of leather tanning process, adopting a novel approach that augments 3D content upon a physical scale model of an old tannery. This approach pursues to transmit the cultural value of traditional craftmanship to visitors of the building and associate its architectural elements to its history and use. A user evaluation was conducted aiming to measure the users’ engagement, learning, and experience using the installation. The encouraging results led to a follow-up study about the impact of the physical scale model on the experience. Two variations of the experience have been studied, one with a physical scale model and one with a digital-only version in a between-subject design. The results of the two studies provide evidence that the proposed approach generated a positive user experience and evident learning gain and was considered easy to use, highlighting its potential to be widely adopted in buildings with architectural value.

Development of masked silica tanning system for sustainable leather production.

Amid mounting pressure on the long-term recyclability of chromium in tanned leather and the associated environmental hazards, the quest for an alternative, cleaner tanning system has gained tremendous momentum. In this context, our study explores the remarkable potential of silicates as a versatile platform for skin/hide tanning, circumventing the inherent risks and ecological threats posed by chromium exposure and leaching. We present an alternative approach of using a silica-based tanning system, employing a Taguchi model, to optimize a masked silica (MaSil) tanning product/process for achieving effective collagen stabilization. Our results demonstrate the significant advancements made in hydrothermal denaturation temperature, reaching an impressive 79 °C through precise Taguchi parameters-5% SiO2, masked with 0.3 mole of citrate salt, and a tanning process fixation pH of 4.5. Notably, the mechanical strength analysis reveals compliance with the stringent upper leather recommendation standards, validating the practicality and quality of MaSil crust leather. Moreover, our research highlights the unprecedented environmental benefits of the first reported application of Taguchi's approach to the MaSil tanning system. The developed tanning system remarkably reduces total dissolved solids (TDS), biological oxygen demand (BOD), chemical oxygen demand (COD), and overall water load by 68.4%, 25.4%, 59.5%, and 33.7%, respectively, heralding a promising era of water and environmental sustainability in the leather sector. This study holds the potential to transform leather production, wherein the envisioned future on the use of the Taguchi model and optimized MaSil tanning system could find a place in shaping a cleaner, greener, and more sustainable leather industry.

Assembly and analysis of the genome of Notholithocarpus densiflorus.

Tanoak (Notholithocarpus densiflorus) is an evergreen tree in the Fagaceae family found in California and southern Oregon. Historically, tanoak acorns were an important food source for Native American tribes, and the bark was used extensively in the leather tanning process. Long considered a disjunct relictual element of the Asian stone oaks (Lithocarpus spp.), phylogenetic analysis has determined that the tanoak is an example of convergent evolution. Tanoaks are deeply divergent from oaks (Quercus) of the Pacific Northwest and comprise a new genus with a single species. These trees are highly susceptible to "sudden oak death" (SOD), a plant pathogen (Phytophthora ramorum) that has caused widespread deaths of tanoaks. In this study, we set out to assemble the genome and perform comparative studies among a number of individuals that demonstrated varying levels of susceptibility to SOD. First, we sequenced and de novo assembled a draft reference genome of N. densiflorus using cobarcoded library processing methods and an MGI DNBSEQ-G400 sequencer. To increase the contiguity of the final assembly, we also sequenced Oxford Nanopore long reads to 30× coverage. To our knowledge, the draft genome reported here is one of the more contiguous and complete genomes of a tree species published to date, with a contig N50 of ∼1.2 Mb, a scaffold N50 of ∼2.1 Mb, and a complete gene score of 95.5% through BUSCO analysis. In addition, we sequenced 11 genetically distinct individuals and mapped these onto the draft reference genome, enabling the discovery of almost 25 million single nucleotide polymorphisms and ∼4.4 million small insertions and deletions. Finally, using cobarcoded data, we were able to generate a complete haplotype coverage of all 11 genomes.

Economic efficiency of leather treated with zeolite after the pickling process

Raw bovine leather (hide) undergoes a series of manufacturing processes to obtain a finished leather or semi-finished leather, which as such can last for a long period without damage to the hide. The damage by bacteria in the tannery is almost entirely restricted to the soaking operation, but some damages occur under poor storage conditions after pickling and in a wet stage after tanning. Protection against microorganisms is still needed because long periods of storage in moisture and heat create conditions suitable for the rapid growth of microorganisms, which can cause considerable hide damage. The development of microorganisms causes damage that affects the final quality and usability of the leather. In order to avoid damage, the hide undergoes a process of washing and removing microorganisms, before the tanning process. This paper studies and compares the costs of protection from microorganisms of hide treated with bath containing zeolite and citric acid, after the process of pickling, in relation to the costs of removing microorganisms that occur due to poor storage conditions. The costs are one of the elements for determining economic efficiency. This comparison provides an insight into the costs of these processes and their cost-profitability.