December 2018 Abstracts

Screening of Bacteriocin Production from Moderately Halophilic Skin Isolates to Inhibit Moderately Halophilic Bacteria Producing Protease and Lipase

by P. Caglayan and M. Birbir

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.

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Tone in Tone Dyeing: Attempt to use Dye Encapsulated Silica Nanospheres in Leather Dyeing

by Sathya Ramalingam and Jonnalagadda Raghava Rao

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.

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Analyses of Nitrogen Metabolism Functional Microbial Community in Aerobic Tanks of Hydrolysis Acidification and Multistage Aerobic Process for Tannery Wastewater

by Ding Shaolan, Tian Qianqian, Cao Kai, Li Hua and Yang Jianjun

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.

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Closed-loop Liming and Chrome Tanning Systems in Full-scale Wet Blue Manufacture. Operational Management, Technical and Environmental Advantages

by Richard Daniels, Jiasheng Su, Falei Zhang and Zhuangdou Zhang

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.

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