Leather and Footwear Journal

Volume 20, no 4

Contents
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DETERMINATION OF THE TOLERANT CONCENTRATION OF Eisenia fetida TO CHROME SOLID RESIDUES FROM TANNERY
- Pages 345-352
  Robert BULEJE DEL CARPIO*, Liliana MARRUFO-SALDAÑA*
  - Productive Innovation and Technological Transfer Center of Leather, Footwear and related industries (CITEccal Lima).
    Technological Institute of Production (ITP), Caquetá Ave. 1300, Rímac, 15094, Lima, Perú, rbuleje@itp.gob.pe, lmarrufo@itp.gob.pe
  ABSTRACT. The tanning industry, although it is characterized by the use of the skin waste originated by the cattle raising, in contrast, produces huge volumes of waste, among which chrome shavings stand out due to their high percentage of chromium. The objective of this research was to determine the concentration where earthworms (Eisenia fetida) could tolerate chrome shavings, in order to evaluate the potential for degradation of these wastes through biological treatment. To determine the tolerant concentration, an experimental design was established that included as factors, the time of exposure in weeks (0-11) and the concentrations of exposure: 0.01, 0.02, 0.04, 0.08, 0.12 and 0.16 grams of shavings per grams of substrate. The response variable was the mortality rate. Each treatment was performed in triplicate and a negative control was included. Statistical treatment was performed using ANOVA and multiple comparison tests at 95% confidence with the statistical complement Real Statistics, Statgraphics and Yupana software. The tolerant concentration established in the study was 0.04 g/g (grams of shavings per grams of substrate) which is equivalent to 636 mg/kg (based on dry weight) expressed in weight of chrome per weight of compost.
  
  KEY WORDS: chromium, chrome shavings, Eisenia fetida, bioassay
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LASER MODIFICATION OF LEATHER AND FUR SURFACE TO IMPROVE ITS QUALITY WHEN CONDUCTING FINISHING OPERATIONS
- Pages 353-360
  Akmal Yusupovich TOSHEV¹*, Mariya Ivanovna MARKEVICH², Tulkin Jumayevich KODIROV¹, Valentina Illarionovna ZHURAVLEVA³
  - ¹Tashkent Institute of Textile and Light Industry, 100100, Shohzhahon-5, Tashkent, Republic of Uzbekistan, email: akmal-toshev-yu@mail.ru
  - ²Physical-Technical Institute of the NAS of Belarus, 220141, Academician Kuprevich street 10, Minsk, Belarus 712518272
  - ³Military Academy of the Republic of Belarus, 220057, Minsk, Independence Ave 220, Minsk, Belarus
  ABSTRACT. The article discusses the problems of activation of the surface of the leather tissue by laser exposure, changes in the morphology of the surface of the leather tissue during laser processing, and subsequent covering dyeing of the leather. It is shown that laser treatment changes the structure of the surface of the leather tissue, the bundles of collagen fibers are split, the structure becomes loose, which increases the diffusion of the coating dye reagents, and their reactivity increases without chemical modification. In the process of grinding leather fabric, it is finely cleaned which improves adhesion of the coating paint to the surface of the leather fabric, which improves the quality of leather fabric products. It was shown that laser exposure under the conditions found (pulses with an interval of 3 μs, a duration of 10 ns) does not cause destruction and configuration changes in collagen.
  
  KEY WORDS: leather tissue, pigment concentrate, casein, acrylic aldehyde, copolymer emulsion of butyl acrylate, methyl methacrylate and acrylic acid, coating dyes, laser radiation, diffusion, surface structure of leather tissue, collagen fibers, elemental analysis, magnetic resonance, adhesion
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EFFECTIVENESS OF PRESSURE-RELIEVING SHOES/INSOLES ON LOWERING THE PLANTAR PRESSURE OF DIABETIC FOOT: A META-ANALYSIS
- Pages 361-374
  Xinrong ZHI¹, Weiping WANG², Bo XU¹, Jin ZHOU^{1, *}
  - ¹National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University; Chengdu 610065, P. R. China; 1436160237@qq.com, 228447319@qq.com, zj_scu@scu.edu.cn
  - ²452 Hospital of PLA; Chengdu 610065, P. R. China; wwp021006@sina.com
  ABSTRACT. Since current reports demonstrated a higher prevalence of foot ulcers in diabetic patients who suffer from foot complication, the preventing occurrence of foot ulcers were the primary target in foot care. Clinical consensus introduced a variety of pressure-relieving products to diabetic patients and clinicians prescribed these products to their patients and recommended them used in daily life. However, available data were still controversial and whether these products could effectively reduce plantar pressure or not were uncertain. Thereby, this meta-analysis aimed first to summary all relevant findings in current database and secondly to explore whether pressure-relieving insoles/shoes can really relieve plantar pressure and what’s differences between customized products (shoes/insoles) and standard ones in reducing plantar pressure. We first searched published articles cited from Web of Science, Medline via OVID, CINAHL, SCOPUS, INFORMIT, Cochrane Central and EMBASE via OVID. Then we filtered observational studies reporting experimental effect of pressure-relieving insoles/ shoes. Meanwhile, we set up primary outcome as overall mean peak plantar pressure (MPP) and secondary outcomes as MPP at various plantar regions and MPP at insoles/shoes with various structure designs. Our results show that pressure-relieving products (shoes/insoles) did lower the amplitude of pressure concentration; effect of custom-made and pre-fabricated products on pressure-relieving were similar. These findings suggested that no matter pressure-relieving products were custom-made or prefabricated standard one, if they were designed targeting to increase overall plantar contact areas, such as designed based on plantar model, or to provide extra arch supports or plug-in structures to transfer pressure concentration, they were all useful in diabetic foot care to prevent occurrence of ulceration. Overall, it is recommended that diabetic patients shall wear pressure-relieving insoles/shoes while walking.
  
  KEY WORDS: diabetes mellitus, footwear, foot ulcer, plantar pressure
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CHARACTERIZATION AND PRODUCTION OPTIMIZATION OF KERATINASE FROM THREE Bacillus STRAINS
- Pages 375-384
  Raden Lukas Martindro Satrio Ari WIBOWO¹, Ragil YULIATMO^{2, *}
  - ¹Laboratory of Microbiology and Enzyme, Politeknik ATK Yogyakarta, Special District of Yogyakarta, 55281, Indonesia
  - ²Laboratory of Beam House Operation and Tanning, Politeknik ATK Yogyakarta, Special District of Yogyakarta, 55281, Indonesia, ragilyuliatmo@atk.ac.id
  ABSTRACT. Indonesia has large coastal areas. The fisheries are good for exploitation. In the previous studies, bacteria producing keratinase were isolated from fish market waste. Keratinase enzyme is able to degrade keratin on the skin. Enzyme activity is influenced by external conditions, such as pH, temperature, and incubation time. The study aimed to investigate the characteristics and the optimal conditions of the keratinase production. The materials used were keratinase from three Bacillus strains: Bacillus thuringensis BRAW_PT, Bacillus aerius BRAW_ PB, and Bacillus subtilis BRAW_PI. The keratinase was investigated by sodium dodecyl sulfate (SDS PAGE) and nondenaturing polyacrylamide gel electrophoresis (Native PAGE). Conditions of the production were optimized by pH, temperature and incubation time on enzyme activity. The molecular weights of all keratinases from Bacillus species were 94.803 kDa and 70.115 kDa. The optimum activity of keratinase from B. thuringensis BRAW_PT and B. firmus BRAW_PI was obtained at pH 8, while keratinase from B. aerius BRAW_PB was optimal at pH 6-8. Keratinase from B. thuringensis BRAW_PT has maximum activity at 25°C, whereas keratinase from B. aerius BRAW_PB and B. firmus BRAW_PI at 29°C. All keratinases from Bacillus species are optimal at 90 minutes incubation. Based on the principal component analysis (PCA), B. thuringensis BRAW_PT was discriminated from the other enzymes.
  
  KEY WORDS: production optimization, keratinase enzyme, unhairing, fish market waste
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DETERMINATION OF 24 PESTICIDES RESIDUES IN LEATHER PRODUCTS BY SOLID-PHASE MICROEXTRACTION COUPLED WITH GAS CHROMATOGRAPHY–MASS SPECTROMETRY
- Pages 385-404
  Jinlan DAI^{1, 2, 3}, Honglei YIN³, Hang WEI⁴, Lei ZHOU⁵, Minghua LIU^{6, *}
  - ¹College of Chemical Engineering, Fuzhou University, Fuzhou, 350116, Fujian Province, China; 29171239@qq.com
  - ²Technical Center of Fuzhou Customs District of P.R.China, 350003, China
  - ³Fujian Key Laboratory for Technology Research of Inspection and Quarantine, 350003, China; 21558049@qq.com
  - ⁴Institute of Quality Standards & Testing Technology for Agro-products, Fujian Academy of Agricultural Sciences/Fujian Key Laboratory of Agro-products Quality and Safety, Fuzhou 350003, China; 349537891@qq.com
  - ⁵Technical Center for Safety of Industrial Products of Tianjin Customs District of P .R.China, 300308, China; zhouleiciq@126.com
  - ⁶College of Environment and Resource, Fuzhou University, Fuzhou 350116, Fujian Province, China; mhliu2000@fzu.edu.cn
  ABSTRACT. Considering the high content of oil and complex residual additives in leather samples, a new analytical method based on the solidphase extraction technique and gas chromatography-selected ion monitoring mass spectrometry (GC-SIM-MS) was developed to determine 24 organic compounds involving the organochlorine pesticides (OCPs), organophosphorous pesticides (OPPs) and pyrethroids pesticides residues in leather. The extraction conditions (such as the extraction solution, purification procedure and solid-phase extraction column) were optimized using the positive leather samples based on the recovery rates of the pesticides. The best extraction solution, solid-phase extraction column and chromatography column were n-hexane and ethyl acetate (1+1, volume) mixed solution, Carb-PSA (1.0 g, 6mL) and DB-1701 (length: 30 m, inside diameter: 0.25 mm, film thickness: 0.25 μm). The optimized extraction time and temperature were 20 min and 25°C, respectively. The detection limits of 24 pesticide residues range from 0.05 to 0.10 mg/kg, and the recoveries range from 74% to 116%. The relative standard deviations (RSD, n=6) range from 5.42% to 12.00%. The developed method presented a simple, rapid, sensitive, and inexpensive method to detect 24 pesticides in skin and leather and was successfully applied to the detect them in leather products (cowhide, sheep leather and pig leather).
  
  KEY WORDS: leather, organochlorine pesticides, organophosphorous pesticides, pyrethroids pesticides, GC-MS
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ESTIMATION OF THE ALLOWABLE CONCENTRATION OF CHLORIDES IN SOAKING EFFLUENTS FROM THE TANNING PROCESS USING ECOTOXICOLOGICAL TOOLS
- Pages 405-412
  Ruth MOGOLLON ROPA, Liliana MARRUFO SALDAÑA*, Julio BARRA HINOJOSA*, Rosa CONTRERAS PANIZO, Robert BULEJE DEL CARPIO
  - Productive Innovation and Technological Transfer Center of Leather, Footwear and related industries (CITEccal Lima). Technological Institute of Production (ITP), Caquetá Ave. 1300, Rímac, 15094, Lima, Perú, rmogollonr@uni.pe, lmarrufo@itp.gob.pe, julio.barra.h@uni.pe, rcontreras@itp.gob.pe, rbuleje@itp.gob.pe
  ABSTRACT. The use of sodium chloride for the preservation of pelts and skins destined for tanning is a very widespread technique in Peru, therefore the quantities used of this salt represent high concentrations of chlorides in the liquid effluents that are generated, which can affect the environmental quality of ecosystems and human health. The present study aimed to estimate an allowable concentration of chlorides in tanning effluents using ecotoxicological tools so that it would serve as a guide for the tanning industry and the authorities in their efforts to establish better conservation practices and effluent control parameters, which are currently absent from national environmental legislation. The permissible concentration of chlorides was determined using bioassays with seeds of Lactuca sativa species (lettuce), which was exposed to soaking effluents obtained from local tanneries. The studied species was determined based on sensitivity tests to zinc sulfate (ZnSO₄ ) applied to three commercial lettuce species. The selected lettuce seed presented a germination rate higher than 90%, a CV lower than 30% and an IC₅₀ of 38.97 mg/L of Zn⁺² with a confidence interval between 19.30 mg/L and 58.65 mg/L of Zn⁺². The admissible guide concentration determined for chlorides in soaking effluents from IC₅₀ was 582.30 mg/L with a minimum value of 258.45 mg/L and a maximum of 906.15 mg/L. Additionally, because of the presence of other pollutants in the soaking effluents, such as bactericides, organic matter, enzymes and salts added in soaking process, tests with synthetic solutions of sodium chloride at the same concentrations of the soaking effluents were conducted, to evaluate the effect produced by those substances.
  
  KEY WORDS: waste valorization, chrome shavings, alkaline hydrolysis, tanning process
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DEVELOPING INNOVATIVE FOOTWEAR DESIGNS: EMPIRICAL EVIDENCE FROM INDONESIA
- Pages 413-424
  David Sukardi KODRAT, Tina MELINDA*, Denpharanto A. KRISPRIMANDOYO
  - Universitas Ciputra, Citraland – Surabaya, Indonesia, david.kodrat@ciputra.ac.id, tina.melinda@ciputra.ac.id, agungkris@ciputra.com
  ABSTRACT. This research aims to develop innovative footwear designs using Modified Design Thinking. This research is a qualitative research with Focus Group Discussion (FGD) as data source. Additionally, Modified Design Thinking was used to analyse the research data. The research findings reinforce the use of Modified Design Thinking in developing innovative footwear designs by identifying the needs of potential customers. Furthermore, local culture is believed to be the most influential factor in footwear design. As such, the innovation process in Indonesia is unique as it incorporates local culture into the creation of footwear design. This research enriches the existing footwear design innovation from the customers’ perspective by using local culture as the main innovation element.
  
  KEY WORDS: innovation, footwear design, Modified Design Thinking, local culture
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THE INFLUENCE OF CHITOSAN TOWARDS ANTIBACTERIAL PROPERTIES IN NATURAL LEATHER
- Pages 425-434
  Mustafidah UDKHIYATI^{1, *}, Nur Mutia ROSIATI¹, Fitrilia SILVIANTI²,
  - ¹Department of Leather Processing Technology, Politeknik ATK Yogyakarta, Sewon, Bantul, 55188, Yogyakarta, Indonesia, ukyfida@gmail.com
  - ²Department of Rubber and Plastic Processing Technology, Politeknik ATK Yogyakarta, Sewon, Bantul, 55188, Yogyakarta, Indonesia
  ABSTRACT. The abundant hydroxyl groups (-OH) of vegetable tanned leather enhances the bacterial growth possibility. In this work, antibacterial vegetable tanned leather was developed taking advantage of chitosan antibacterial activity. Different chitosan utilization method was conducted, namely drum impregnation and spraying. Antibacterial testing was carried out using agar diffusion method to identify the effect of chitosan against Gram-positive bacteria (Staphylococcus aureus). The results showed that the use of 1% (w/v) chitosan by spraying method tends to be more effective in improving the antibacterial properties of vegetable tanned leather. While, the leather sample of drum impregnation at initial pH 4 has the lowest antibacterial activity among others. The results of FTIR analysis showed that there was no significant difference between control and chitosan modified tanned leather, confirming the similar functional groups between it.
  
  KEY WORDS: leather, antibacterial, chitosan
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