Alkali-free method of hide preparation for tanning

Valeika, Virgilijus; Beleska, K.; Sirvaityte, J.

doi:10.1590/s0104-66322012000200012

Cited by 15 publications

(10 citation statements)

References 6 publications

(6 reference statements)

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“…( 2011 ), Valeika et al. ( 2012 ), FAO ( 1996 ), Biosecurity New Zealand ( 2007 ) and ENEA ( 2020 ), it commonly includes: Trimming: mechanical removal of unwanted parts. Soaking: re‐hydration and washing to remove substances like dirt, blood and salt (a bactericide can be added).…”

Section: Assessmentmentioning

confidence: 99%

Inactivation of indicator microorganisms and biological hazards by standard and/or alternative processing methods in Category 2 and 3 animal by‐products and derived products to be used as organic fertilisers and/or soil improvers

Koutsoumanis¹,

Allende²,

Bolton³

et al. 2021

EFS2

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The European Commission requested EFSA to assess if different thermal processes achieve a 5 log 10 reduction in Enterococcus faecalis or Salmonella Senftenberg (775W) and (if relevant) a 3 log 10 reduction in thermoresistant viruses (e.g. Parvovirus ) as well as if different chemical processes achieve a 3 log 10 reduction of eggs of Ascaris sp., in eight groups of Category 2 and 3 derived products and animal by‐products (ABP). These included (1) ash derived from incineration, co‐incineration and combustion; (2) glycerine derived from the production of biodiesel and renewable fuels; (3) other materials derived from the production of biodiesel and renewable fuels; (4) hides and skins; (5) wool and hair; (6) feathers and down; (7) pig bristles; and (8) horns, horn products, hooves and hoof products. Data on the presence of viral hazards and on thermal and chemical inactivation of the targeted indicator microorganisms and biological hazards under relevant processing conditions were extracted via extensive literature searches. The evidence was assessed via expert knowledge elicitation. The certainty that the required log 10 reductions in the most resistant indicator microorganisms or biological hazards will be achieved for each of the eight groups of materials mentioned above by the thermal and/or chemical processes was (1) 99–100% for the two processes assessed; (2) 98–100% in Category 2 ABP, at least 90–99% in Category 3 ABP; (3) 90–99% in Category 2 ABP; at least 66–90% in Category 3 ABP; (4) 10–66% and 33–66%; (5) 1–33% and 10–50%; (6) 66–90%; (7) 33–66% and 50–95%; (8) 66–95%, respectively. Data generation on the occurrence and reduction of biological hazards by thermal and/or chemical methods in these materials and on the characterisation of the usage pathways of ABP as organic fertilisers/soil improvers is recommended.

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Section: Assessmentmentioning

confidence: 99%

Inactivation of indicator microorganisms and biological hazards by standard and/or alternative processing methods in Category 2 and 3 animal by‐products and derived products to be used as organic fertilisers and/or soil improvers

Koutsoumanis¹,

Allende²,

Bolton³

et al. 2021

EFS2

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“…Second piece was unhaired according to enzymatic method: H 2 O -200%, temperature 25°C, enzyme preparation (EP) NovoBate WB (Novo Nordisk, Denmark) -0.6 %, CH 3 COONa -2%, CH 3 COOH -0.3%, duration 6 hours (Valeika et al, 2012). After the process the wool was removed from the skin sample using blunt knife, washed three times: H 2 O 1000%, temperature 42°C, duration 20 min., dried at ambient temperature and used as enzymatically unhaired wool (wool 2).…”

Section: Preparations Of Hair Samplesmentioning

confidence: 99%

Biodegradability of Hair as a Waste of Leather Industry

Valeika¹,

Jankauskaitė²,

Beleska³

et al. 2018

The International Conference on Advanced Materials and Systems

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Leather industry is one of the sources, which releases keratin-containing wastes. Still now, most of the tanneries are following hair-burning process, which contribute high amount of COD, BOD, TDS etc., to the effluent. This is a reason why numerous investigations are done reaching to replace the hair burning process by hair save unhairing: enzymatic or unhairing with hair immunization. The aim of the study was to investigate the biodegradability peculiarities of native hair, hair after enzymatic unhairing and hair obtained by unhairing with immunization effect. The soil burial test was carried out and the biodegradability of the wool was estimated. The biodegradability of the wool was estimated analysing their mass loss and fungal colonization. It was established that hair samples behave differently during the exposition in the soil: there were determined different species of fungi after 3-month exposition. The mass loss was different as well. Accordingly, the hair obtained after different method of unhairing are different in their properties as well. The different properties should mean different behaviour of the hair during biodegradation.

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“…In such a case, enzymes are used for the main unhairing and oxidisers are used for degrading of hair remnants. The proteases acting in alkaline or acidic medium can be applied in such cases [ 17 , 18 ]. It should be noted that the oxidative–enzymatic unhairing process has also not been adopted in practise.…”

Section: Introductionmentioning

confidence: 99%

Enzymes for Leather Processing: Effect on Pickling and Chroming

2021

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Recently, increasing attention has been paid to the application of enzymes in a wide variety of leather production processes. The aim of the present study was to investigate the action of enzymatic pickling on derma’s collagen and the influence of this action on subsequent processes and properties of chromed and finished leather. The application of active in acidic medium proteolytic enzymes in the pickling process led to an additional impact on derma structure: collagen was more strongly affected and the porosity of the pelt dermis was reduced, but the hide became more thermally stable. The enzymatically pickled pelt bonded more chromium and reached higher shrinkage temperature while chroming; dyes penetrated deeper; such leather bonded more fatliquors. On the other hand, the action of enzymes worsened the physical–mechanical properties of the leather, as the experimental leather was weaker than the conventional one. The first was characterised by weaker grain layer and had significantly higher relative elongation. Therefore, as some properties improve and others worsen during such a process, the application of every enzyme should be carefully investigated and optimized to produce a leather with defined properties.

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Alkali-free method of hide preparation for tanning

Cited by 15 publications

References 6 publications

Inactivation of indicator microorganisms and biological hazards by standard and/or alternative processing methods in Category 2 and 3 animal by‐products and derived products to be used as organic fertilisers and/or soil improvers

Inactivation of indicator microorganisms and biological hazards by standard and/or alternative processing methods in Category 2 and 3 animal by‐products and derived products to be used as organic fertilisers and/or soil improvers

Biodegradability of Hair as a Waste of Leather Industry

Enzymes for Leather Processing: Effect on Pickling and Chroming

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