Screening of bacteriocin production from moderately halophilic skin isolates to inhibit moderately halophilic bacteria producing protease and lipase
Bacteriocins, produced from a wide variety of microorganisms to inhibit or kill different species of bacteria, have received increased attention in different industries. Hence, bacteriocins produced from moderately halophilic skin isolates were examined to demonstrate their inhibitory effect against enzyme-producing (protease or lipase) skin isolates. Eleven identified skin isolates, obtained from salted goat and sheep skins, were used as test isolates. Ten of these isolates (Halomonas halodenitrificans, Halomonas halmophila, Salimicrobium salexigens, Gracilibacillus dipsosauri, Salinivibrio costicola subsp. alkaliphilus, Halomonas venusta, Planococcus rifietoensis, Marinococcus tarijensis, Halomonas eurihalina, Staphylococcus arlettae) showed antimicrobial effect against each other. Although Halomonas halodenitrificans, Salimicrobium salexigens, Halomonas venusta did not produce enzyme, the other isolates produced protease or lipase enzymes. While bacteriocin produced from Halomonas halodenitrificans was found to be effective against enzyme-producing Gracilibacillus dipsosauri, Planococcus rifietoensis and Halomonas eurihalina, bacteriocin of Salimicrobium salexigens was effective against enzyme-producing Salinivibrio costicola subsp. alkaliphilus, Marinococcus tarijensis and Halomonas eurihalina. Bacteriocin of Halomonas venusta was effective against enzyme-producing Halomonas halmophila, Marinococcus tarijensis, Halomonas eurihalina, Idiomarina loihiensis and Staphylococcus arlettae. The maximum bacteriocin production of these skin isolates was obtained at 37°C, pH 7.0, and 10% salt concentration. Antimicrobial activities of the bacteriocins against all test isolates were detected at 10°C-60°C, pH 6.0-8.0 and 3%-20% salt concentrations. Antimicrobial activities of all bacteriocins against test isolates were not detected after the treatment with proteinase K. Minimal inhibitory concentration (MIC) values of the bacteriocins against the test isolates were detected as 1/2, 1/4 or 1/8. Scanning electron micrographs of sheepskins showed that sterile bacteriocins of Halomonas halodenitrificans, Salimicrobium salexigens, Halomonas venusta may be used in leather industry to prevent the growth of protease and lipase producing moderately halophilic bacteria.
JALCA Dec 2018
Tone in tone dyeing: attempt to use dye encapsulated silica nanospheres in leather dyeing
A commercial leather dye was encapsulated into silica by simple microemulsion technique and applied as dyeing agent in leather dyeing process. Comparative studies on the performance of free dye (non-encapsulated) towards encapsulated dye are evaluated. The resultant formation of nanospheres contain dye inside the silica matrix was investigated by UV-Visible, TEM (Transmission Electron Microscopy) and DLS (Dynamic Light Scattering) measurement. The confinement effect was identified by the formation of spherical particles of the silica through encapsulation. On whole the spectroscopic studies showed that the formed silica nanospheres are stable enough to utilize as dyeing agent in leather dyeing process. The performance of encapsulated nanospheres was evaluated by utilizing as dyeing agent for upper and garment leather processing. The dye entrapped inside the silica spheres had better affinity towards the leather as demonstrated by their uniform penetration throughout its cross section and its surface coloring. The dyeing properties of the encapsulated dye were appraised by color and fastness measurement. The results showed that the dyeing characteristics of the experimental leathers were greatly improved by using encapsulated dyes versus their control leathers. Hence the idea of supporting commercial dye on/inside polymeric silica substrate enriched the leather dyeing characteristics and provide the clue for any dye for any substrate.
JALCA Dec 2018
Analyses of nitrogen metabolism functional microbial community in aerobic tanks of hydrolysis acidification and multistage aerobic process for tannery wastewater
The actual tannery wastewater was treated by hydrolysis acidification and multistage aerobic process (A/O3). The growth status of microorganisms in three aerobic tanks was measured with the Biolog microplate method to reflect the ability of metabolizing nitrogen source. In the three aerobic tanks, the functional differences between different nitrogen source metabolism microbial communities in three aerobic tanks were compared and analyzed. The results of the present study have shown that when the concentrations of ammonium chloride and potassium nitrate were low, the metabolic activity of nitrifying bacteria was higher than that of denitrifying bacteria in aerobic tanks. With the increase of concentration of ammonium chloride and potassium nitrate, the metabolic activity of denitrifying bacteria was gradually increased, and gradually higher than that of the nitrifying bacteria metabolism. When the concentrations of ammonium chloride and potassium nitrate were 100 mg/L and 20 mg/L, and the concentrations of ammonium chloride and potassium nitrate were 150 mg/L and 30 mg/L, O1 has the best denitrification effect. However, when the concentrations of ammonium chloride and potassium nitrate were increased, nitrogen load was increased, the denitrification effects of nitrification and denitrifying microorganisms were fluctuated. And the diversity index analyses by five indexes showed that the metabolic capacity of microorganisms to carbon sources is good.
JALCA Dec 2018
Closed-loop liming and chrome tanning systems in full-scale wet blue manufacture. Operational management, technical and environmental advantages
Closed-loop liming/unhairing and chromium tanning systems are now established for the full-scale manufacture of bovine wet blue leathers. The technology ensures full recovery and reuse of the concentrated used processing floats, and four major tanneries are now producing some 72,000 hides per week as high quality wet blue leathers from salted American, European and Australian wet salted hides. These are for their own use, sales, and contract tanning.
In practice there are no discharges or washings for effluent treatment from either the liming/unhairing or the acid/salt pickle and chromium tanning processes. Accordingly, there is no chemical wastage from these two major stages within leather making. There are significant saving in processing chemicals – lime, sodium sulfide/hydrosulfide, salt, acids, chromium tanning agents and water too. The problems associated with treating waste waters from these two environmentally difficult stages are thus totally avoided.
Based on independent on-site surveys within each of these four tanneries, this paper shows how the technology is managed in practice. In particular it shows how the process stabilizes within these processing loops, and how a continuous increase in neutral salts is avoided.
JALCA Dec 2018
The Leather Trades’ Engineers of Massachusetts: Vaughn Machine Co. 1892-1904 Vaughn-Rood Machine Co. 1903-1905. Part 2
The rise of a specific rival to the Vaughn Machine Co. is considered along with major changes in management at the internationally important leather trade engineer, based in Peabody, Massachusetts (MA), United States. By emphasising the essential role of George C. Vaughn in tanning machinery development, it establishes why a new contender – the Vaughn-Rood Machine Co., became a major challenger. It also reflects on the interesting account of how wrangles in the US Courts resulted in the transfer of patents and machinery designs, from the Vaughn Machine Co., to the Turner Tanning Machinery Co. Survival of the old established Vaughn business demanded a change from leather trade machinery into the expanding automotive sector. For a time this seemed to fill the void for the engineering concern. Demise however, soon followed. Subsequent to the brief history of the VaughnRood Machine Co., the paper concludes with the agreed takeover of this business, also by the Turner Tanning Machinery Co., and some of the later enterprises pursued by George C. Vaughn.
JSLTC Nov/Dec 2018
Mechanism of vegetable extracts on preventing the oxidation of chrome(III)
To explore the mechanism whereby hydrolysable tannins and the monomers hydrolysed from hydrolysable tannins in preventing Cr(III) from oxidising into Cr(VI), we selected Valonia, Tara, plus monomers including gallic acid and ellagic acid as test samples to evaluate their complexing ability, reducibility, antioxidation ability and impact on preventing Cr(III) from oxidising into Cr(VI) as well as the relationship between their abilities and impact. With total phenolic value taken as a measurement basis, we took the equivalent quantity of every material based on its total phenolic value, and tested the effect on the same amount of Cr(III) and with the Folin-phenol method to total the number of the active phenolic groups, then we inferred the binding ability from the phenolic group activity. The complexation ability was determined by measuring the decrease of the phenolic value during a given interval in a system where we mixed every material with chrome powder and found the reducibility by using the absorbency method of K3Fe(CN)6 reduction, and analysed the antioxidation ability by DPPH. These abilities are major influential elements in preventing Cr(III) from oxidising into Cr(VI). The relationship between parameters was discovered. The main results were: generally speaking, that the complexing ability of these materials, in order from great to small, is in the order: ellagic acid, Tara, Valonia and gallic acid, which accords with their abilities to prevent Cr(III) from oxidation into Cr(VI) to a large extent. The reducibility and antioxidation effect of these materials from large to small is in the order: ellagic acid>gallic acid>Tara>Valonia, and this has a positive affect on preventing Cr(III) from oxidation into Cr(VI) to quite a large extent, However, the order of reducibility and antioxidation doesnʼt accord with the order of ability to prevent Cr(III) from oxidising into Cr(VI).
JSLTC Nov/Dec 2018
The relationship between the organoleptic properties of leather and the aggregate structure of collagen fibres
Samples of chromed sheep leather were prepared to establish the relationship between the organoleptic properties of leather and its structure after being retanned and oiled. The organoleptic properties and structure of them were characterized by stress-strain analysis, SEM and organoleptic test. The relationship was investigated from the point of fibre mobility. The results show that, when fibre bundles become thin and porosity increases, fibre mobility increases, as does softness, but tightness weakens. With the extent of fibre orientation decreasing, thickness increases, and smoothness decreases. Fullness is a special parameter related to leather thickness and fibre mobility . As collagen fibres have better motion capability when there is a decrease in the degree of orientation, fullness improves.
JSLTC Nov/Dec 2018
The rheological properties of grain leather broiler rabbits
The studies examined the rheological properties of broiler rabbit grain leathers for leather gloves and shoes and determined whether they had the requirements defined by the standard. The study material included grain leathers of two groups of hybrid rabbits, 24 pieces each: Group I: Belgian Giant Gray x Burgundy (BOS x BU), Group II: Belgian Giant Gray x White New Zealand (BOS x BNZ). Broilers rabbit leathers were characterised by high values of strength parameters in static tests. Leather of BNZ x BOS hybrids processed for both gloves and footwear, had higher values of the tested features. However, they did not differ significantly from the results obtained for BOS x BU leathers. The values gave indications for both tests higher than the requirements of the relevant standards. The rheological and organoleptic properties of the rabbit broiler leathers tested proved that they can be used not only for gloves, but also for shoe uppers.
JSLTC Nov/Dec 2018
Synthesis of an amphoteric polymer auxiliary agent and its application to chrome-free leather
In order to reduce the disadvantages of chrome tannage, chrome-free tannage was developed by many technologists and tanneries. However, because of the structures and charge of the tanning materials in the chrome-free tannage, the absorption rate of the chrome-free leather for anionic dyestuffs, re-tanning agents and fatliquors is lower than that of the chrome-tanned leather. Therefore, in order to improve the absorptivity of the chrome-free leather for these products, an amphoteric polymer auxiliary agent was synthesized with methyl-acrylic acid, sodium methylallyl sulfonate and dimethyl diallyl ammonium chloride (DMDAAC) by free radical copolymerization using ammonium persulfate at 80°C for 3 hours. The molar ratio of methyl-acrylic acid, sodium methylallyl sulfonate and dimethyl diallyl ammonium chloride was confirmed to be 1.0/0.3/ 1.0. The structure of the amphoteric polymer auxiliary agent was characterized by FTIR, 1H-NMR, 13C-NMR. The charge and properties of the solution of the amphoteric polymer auxiliary agent were characterised. Applied results of the amphoteric polymer auxiliary on the absorption of chrome-free leather for dyestuff and fatliquor, show that it has strong auxiliary absorptive capacity and the absorptive rate of dyestuff and fatliquor is more than 96%.
JSLTC Nov/Dec 2018
Development of reference materials for inorganic elements in leather powder
Abstract Three reference materials for As, Cd, Co, Cu, Hg, Ni, Pb and Sb – 8 inorganic elements in leather powder were developed with relatively low, middle and high concentrations. The reference materials were prepared by adding an appropriate concentration using industrial process. The concentration range of the three levels is within the ± 200% of the limited value in the China statute Safety Technical Specifications for Childrenʼs Footwear (GB 30585-2014).1 By using 16 units with duplicate analysis, it was shown that the samples were enough to demonstrate the homogeneity of these candidate reference materials. The statistical results from the stability test, also showed no significant trends in both short-term stability test for one week at 40°C and long-term stability test for 23 months. This set of reference materials, were used for more than two certification methods – including isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS), inductively coupled plasma mass spectroscopy (ICP-MS) and inductively coupled plasma optical emission spectroscopy (ICP-OES). The combined relatively standard uncertainties of the reference values were estimated by considering the uncertainties of the analytical methods, homogeneity and stability. The range of the expanded uncertainties of all the elements is from 3% to 5%. The certified reference materials (CRMs) are primarily intended for use in the calibration and validation of procedures for the determination of inorganic elements in in leather or similar leather samples.
JSLTC Nov/Dec 2018