Keratin Powder Research Articles

Electrosprayed recovered wool keratin nanoparticles

This work reports on producing wool keratin nanoparticles through electrospraying. Wool keratin is a natural biodegradable and biocompatible protein. Keratin powder has found application in hygiene, cosmetics, filtration, tissue engineering scaffolds, and controlled drug release. Like other nano materials, the performance of keratin in submicron size range changes drastically. Electrospraying is a technique that is capable of producing nanosized, regular, and spherical particles. To prepare the electrospraying wool keratin solution, keratin was recovered from descaled wool fibers by dissolving it in mercaptoethanol first, and keratin sponge was obtained. Then, the keratin sponge was dissolved in formic acid that provided the electrospraying solution. This research involved primarily an investigation on the effect of important electrospraying conditions such as polymer concentration, feed rate, voltage, and nozzle‐collector distance on the average particle size of the electrosprayed nanoparticles. The results showed that the proper concentration of keratin in formic acid for the electrospraying keratin nanoparticle was about 0.5% (w/v). As far as electrospraying conditions are concerned, decreasing feed rate and increasing nozzle‐collector distance led to lower average particle size. Voltage did not show a practically significant effect on the average particle size. The average size of the electrosprayed keratin nanoparticles fabricated in this work lies in the range of 36–72 nm. Fourier transform infrared Fourier transform infrared (FTIR) spectra showed that electrosprayed keratin nanoparticles contain –SO2–S– and –SO–S– linkages. Copyright © 2014 John Wiley & Sons, Ltd.

Papain Activity in Dextran Solution for Keratin Hydrolysis

High concentration of polymer solution in cosmetics has the essential role in keeping water on peel of skin. This study includes the papain activity in the high concentrated dextran solution for keratin hydrolysis. Papain is the industrial and a representative hydrolase. The concentration of dextran was ranged to 100 g/L. In the increasing concentration of dextran, the activity of papain decreased due to the low diffusivity of papain and substrate. Even in concentrated dextran solution, keratin powder was possible to be hydrolyzed at the high efficiency.

Biochemical and Structural Characterization of a Detergent Stable Alkaline Serine Keratinase from Paenibacillus Woosongensis TKB2: A Potential Additive for Laundry Detergent

A monomeric alkaline keratinolytic serine protease with a molecular weight 190.24 kDa was purified from Paenibacillus woosongensis TKB2 in submerged fermentation using waste chicken feather as substrate. The purified keratinase was highest activity at pH 9.0 and 50 °C, requiring Mo+ for increasing fourfold enzyme activities, showed substrate specificity for keratin powder. The Km and Vmax for the enzyme was 1.4 mg/ml and 251.1 U/ml respectively. An initial analysis of the circular dichroism spectrum in the ultraviolet range revealed that the protease is predominantly an α-helix structure. In the presence of 7 mg/ml (w/v) detergents, the protease was active and retained 40–90 % activity. Therefore, it may have a possible application in laundry formulations. The keratinase combined with detergent was able to destain blood, fruit juice and turmeric stained cloth within 30 min without damaging the fabric structure and strength.

Gaseous byproducts from high‐temperature thermal conversion elemental analysis of nitrogen‐ and sulfur‐bearing compounds with considerations for δ2H and δ18O analyses

High-temperature, conversion-reduction (HTC) systems convert hydrogen and oxygen in materials into H2 and CO for δ(2)H and δ(18)O measurements by isotope ratio mass spectrometry. HTC of nitrogen- and sulfur-bearing materials produces unintended byproduct gases that could affect isotope analyses by: (1) allowing isotope exchange reactions downstream of the HTC reactor, (2) creating isobaric or co-elution interferences, and (3) causing deterioration of the chromatography. This study characterizes these HTC byproducts. A HTC system (ThermoFinnigan TC/EA) was directly connected to a gas chromatograph/quadrupole mass spectrometer in scan mode (m/z 8 to 88) to identify the volatile products generated by HTC at conversion temperatures of 1350 °C and 1450 °C for a range of nitrogen- and sulfur-bearing solids [keratin powder, horse hair, caffeine, ammonium nitrate, potassium nitrate, ammonium sulfate, urea, and three nitrated organic explosives (PETN, RDX, and TNT)]. The prominent HTC byproduct gases include carbon dioxide, hydrogen cyanide, methane, acetylene, and water for all nitrogen-bearing compounds, as well as carbon disulfide, carbonyl sulfide, and hydrogen sulfide for sulfur-bearing compounds. The 1450 °C reactor temperature reduced the abundance of most byproduct gases, but increased the significant byproduct, hydrogen cyanide. Inclusion of a post-reactor chemical trap containing Ascarite II and Sicapent, in series, eliminated the majority of byproducts. This study identified numerous gaseous HTC byproducts. The potential adverse effects of these gases on isotope ratio analyses are unknown but may be mitigated by higher HTC reactor temperatures and purifying the products with a purge-and-trap system or with chemical traps.

Scientific Opinion on the substantiation of a health claim related to Cynatine® and maintenance of normal joint mobility pursuant to Article 13(5) of Regulation (EC) No 1924/2006

Following an application from Roxlor Nutra LLC, submitted pursuant to Article 13(5) of Regulation (EC) No 1924/2006 via the Competent Authority of Belgium, the Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to deliver an opinion on the scientific substantiation of a health claim related to Cynatine® and maintenance of normal joint mobility. The Panel considers that Cynatine®, which is a keratin powder extracted from sheep wool, is sufficiently characterised. The claimed effect proposed by the applicant refers to “joint flexibility”. The Panel considers that maintenance of normal joint mobility is a beneficial physiological effect. The applicant presented one unpublished human intervention study as being pertinent to the health claim. The Panel notes that the study was specifically designed to identify patients with clinical diagnosis of osteoarthritis, and considers that normal cells and tissues are genetically (gene expression) and functionally different from osteoarthritic cells and tissues, and therefore may respond differently to interventions with exogenous substances. In addition, the mechanisms involved in the onset and/or progression of osteoarthritis are largely unknown. It would have to be established, therefore, that an intervention which has an effect on the progression of the disease (in patients with osteoarthritis) would also have an effect on its onset (subjects without the disease). The Panel considers that no conclusions can be drawn from this study for the scientific substantiation of the claim. The Panel concludes that a cause and effect relationship has not been established between the consumption of Cynatine® and maintenance of normal joint mobility.

High yield preparation of keratin powder from wool fiber

A descaling and oxidation pretreatment was employed to maximize the yield of cortical cells in the disintegration process of wool fiber. The results indicated that the productivity of intact cortical cells was greatly increased by moderate oxidation pretreatment in 1.6 % per-acetic acid within 2 h, but the yield would be decreased by further oxidation pretreatment. In order to give a reasonable explanation for this fact, the effect of the increasing time of oxidation pretreatment on the yield of intact cortical cells was investigated by means of spectral analysis using FT-IR and XRD. The intensity of the peak at 1040 and 1173 cm−1 in FT-Infrared spectrum gradually increased with increasing oxidation pretreatment time, suggesting that more and more SS bonds were cleaved to form cysteic acid. X-ray Diffraction investigation showed that the crystallinity of wool fiber obviously decreased when the time of oxidation pretreatment exceeded 2 h. The combined results of FT-IR and XRD revealed that SS bonds in the amorphous region of wool fiber were first cleaved in the fiber components. The selective cleavage of SS bonds in the amorphous region by the appropriate oxidation pretreatment can effectively decrease the bonding force between the components of wool fiber and enhance the yield of intact cortical cells.

Production of feather keratin nanopowder through electrospraying

A small amount of chicken feather, a waste product but rich in protein (keratin), has applications in filters as well as reinforcing polymers and papers. To make a good use of this waste, its keratin must be recovered. The recovered keratin has useful applications in cosmetics, food, biodegradable films and coatings. Keratin powder can be produced through a number of techniques such as milling or spray drying, with drawbacks like high particle size and nonuniform shape. The aim of this study was to produce keratin nanopowder through electrospraying a solution of recovered feather keratin. It was found that trifluoroacetic acid was a suitable solvent. Moreover, the results showed that electrospraying is able to produce uniform size and spherical shaped keratin nanopowder with an average particle size as low as 53nm. Also, it was ascertained that decreasing concentration and feed rate as well as increasing needle–collector distance and voltage up to18kV, decrease the average particle size of keratin nanopowder. FT-IR and XRD studies showed that crystallinity of electrosprayed keratin is less than raw keratin.

Investigation of preparation techniques for δ2H analysis of keratin materials and a proposed analytical protocol

Accurate hydrogen isotopic measurements of keratin materials have been a challenge due to exchangeable hydrogen in the sample matrix and the paucity of appropriate isotopic reference materials for calibration. We found that the most reproducible δ(2)H(VSMOW-SLAP) and mole fraction of exchangeable hydrogen, x(H)(ex), of keratin materials were measured with equilibration at ambient temperature using two desiccators and two different equilibration waters with two sets of the keratin materials for 6 days. Following equilibration, drying the keratin materials in a vacuum oven for 4 days at 60 °C was most critical. The δ(2)H analysis protocol also includes interspersing isotopic reference waters in silver tubes among samples in the carousel of a thermal conversion elemental analyzer (TC/EA) reduction unit. Using this analytical protocol, δ(2)H(VSMOW-SLAP) values of the non-exchangeable fractions of USGS42 and USGS43 human-hair isotopic reference materials were determined to be -78.5 ± 2.3 ‰ and -50.3 ± 2.8 ‰, respectively. The measured x(H)(ex) values of keratin materials analyzed with steam equilibration and N(2) drying were substantially higher than those previously published, and dry N(2) purging was unable to remove absorbed moisture completely, even with overnight purging. The δ(2)H values of keratin materials measured with steam equilibration were about 10 ‰ lower than values determined with equilibration in desiccators at ambient temperatures when on-line evacuation was used to dry samples. With steam equilibrations the x(H)(ex) of commercial keratin powder was as high as 28%. Using human-hair isotopic reference materials to calibrate other keratin materials, such as hoof or horn, can introduce bias in δ(2)H measurements because the amount of absorbed water and the x(H)(ex) values may differ from those of unknown samples. Correct δ(2)H(VSMOW-SLAP) values of the non-exchangeable fractions of unknown human-hair samples can be determined with atmospheric moisture equilibration by normalizing with USGS42 and USGS43 human-hair reference materials when all materials have the same powder size.

Removal of mercury (II) from aqueous solution by adsorption on keratin powder prepared from Algerian sheep hooves

The batch removal of mercury (II) from aqueous solution using keratin powder (size <63 µm) prepared from steamed Algerian sheep hooves was investigated. The influence of sorption time, initial pH, and initial concentration of Hg (II) was evaluated. It is shown that steamed hoof powder from Algerian sheep hooves has a relatively high adsorption capacity for Hg (II). pH values between 2 and 10 have no effect on the sorption of Hg (II). The adsorption equilibrium was established in 3 h. The equilibrium data were described well by the Freundlich model. A comparison of kinetic models applied to the adsorption of Hg (II) on the Algerian sheep hoof powder was evaluated for the pseudo-first-order and pseudo-second-order models. Results show that the pseudo-second-order model was found to correlate well the experimental data.

A novel mycological analysis valuable for evaluating therapeutic efficacy of antimycotics against experimental dermatophytosis in guinea pigs

Although antimycotic effects are mainly evaluated with regard to whether or not the fungi grow from a specimen obtained from the drug-treated skin, the potential for discrepancies in skin specimens in which the fungi are grown has not been evaluated, in the experimental tinea model. In this study, to evaluate the therapeutic effectiveness of antimycotic agents against fungal skin infection, a novel form of mycological assessment, which focuses on the size of colonies grown from skin specimens was examined and developed. When microconidia of Trichophyton mentagrophytes were inoculated onto a Sabouraud dextrose agar (SDA) plate and incubated at 27 degrees C for 5 days, a linear relationship was observed between the growth area of mycelia and the logarithm of the quantity of microconidia. This relationship between the growth area and the logarithm of the number of T. mentagrophytes microconidia did not change with the addition of skin homogenate and/or keratin powder. Next, the number of fungi in skin blocks attendant upon experimental, cutaneous infection in guinea pigs was evaluated and analyzed via a calibration curve, determined based on a microconidium suspension of T. mentagrophytes. Estimates of severity of dermatophytic infection in experimental animals were parallel to, but more reliable than, results obtained via the conventional mycological method (fungus-positive skin ratio of treated skin) in culture studies of infected dermal tissues. This new analytical method may also be applicable to the in vivo assessment of the therapeutic effect against dermatophytosis experimentally produced in guinea pigs.

Novel approach to fabricate keratin sponge scaffolds with controlled pore size and porosity

A compression-molding/particulate-leaching (CM/PL) method was developed to fabricate S-sulfo keratin sponges with the controlled pore size and porosity. The S-sulfo keratin was extracted from wool and was then spray-dried to give S-sulfo keratin powder. The S-sulfo keratin powder mixed with urea in advance was compression-molded together with the sieved NaCl particulates above the melting temperature of urea. The following removal of the salts and urea in water created the sponges composed of interconnected pores and the continuous S-sulfo keratin matrix. The S-sulfo keratin sponges were strong enough to handle and water-insoluble. By contrast, the sponges prepared without urea were very fragile and readily collapsed, because most of S-sulfo keratin matrix remained powdery. The pore size was in good accordance with the size of the salts, indicating that the pores were formed by leaching-out the salts. The S-sulfo keratin sponges with the regulated sizes of pores (<100, 100–300 and 300–500 μm) were fabricated, all of which had more than 90% of the porosity. Thus, CM/PL method is able to give the S-sulfo keratin sponge with the desired pore size and porosity, which might be a good scaffold for the cells in tissue engineering.

Preparation and physicochemical properties of compression-molded keratin films

The S-sulfo keratin was extracted from wool and was then spray-dried to give S-sulfo keratin powder. differential scanning calorimetry analysis showed that the glass transition temperature of S-sulfo keratins became lowered with the increase of moisture content, while perfectly dried S-sulfo keratin powder did not give thermal transition in the temperature range 30–130°C. The compression molding of the S-sulfo keratin powder supplemented with one-tenth weight of water afforded a plastic-like transparent proteinous film above the glass transition temperature. The film obtained from the powder without water addition or compression molded below glass transition temperature partly remained powdery. The film compression molded at 120°C gave the maximum ultimate strength and Young’s modulus, 27.8±2.9 and 1218±80 MPa, respectively. Obtained film was insoluble and slightly swelled in water, but, in the presence of reducing agent, the film significantly swelled at pH 7.0 and even dissolved at pH 9.0, suggesting the relevance of abundant disulfide linkage. The film supported the mammalian cell adhesion and proliferation, demonstrating the biocompatibility of S-sulfo keratin films.

Binding of primaquine to epidermal membranes and keratin

The localisation of primaquine was studied within epidermal membranes following the application of a topical dose. A depth profile was constructed by tape-stripping human epidermis following permeation of a 70 mg ml −1 solution of primaquine in Miglyol 840. Comparative binding studies of primaquine were carried out on isolated human stratum corneum and whole epidermis, using normal and delipidised tissue. An additional study was undertaken using bovine keratin powder as a model of human keratin. The depth profile showed that primaquine decreased with depth and decreasing keratin content, and the total primaquine recovered (15.5 mg cm −2) was 300× the amount of extractable lipid. Binding to delipidised skin was saturable, whereas binding to normal skin was unsaturable, reflecting the high miscibility of drug in the lipid domains as opposed to a finite, but large number of binding sites on the corneocytes. Binding was greater for stratum corneum than stratum corneum plus viable epidermis, probably due to greater accessibility of corneocytes keratin. Binding was dose dependent, although binding to delipidised skin was far greater than to normal skin, demonstrating that primaquine had an affinity for lipoidal regions and an even higher affinity for the proteinaceous domains of the stratum corneum. This was supported by high saturable levels of primaquine binding to bovine horn keratin. The results indicated extensive binding to corneocyte keratin has a significant effect on reservoir formation and the permeability of primaquine across human skin. It is speculated that the large amount of keratin presented at the skin surface may be an evolutionary protective process for the sequestration of ingressing molecules.

Characterization of a New Keratin-Degrading Bacterium Isolated from Deer Fur.

A keratin-degrading bacterium was isolated from soil containing deer fur. An axenic culture of the keratin-degrading bacterium was obtained in liquid culture using a keratin enrichment technique. The isolated bacterium was gram negative and catalase- and oxidase-positive. Transmission electron microscopic observations showed that the bacterium was rod-shaped, 1.0–1.3 μm long and 0.7 μm in diameter. Phylogenetic analysis of 16S rDNA revealed that the new isolate has only 90.6% homology with Stenotrophomonas nitritireducens. Hence, this new bacterium was designated as Stenotrophomonas sp. D-1. The optimum temperature was determined to be 20°C for maximum growth and keratinolytic enzyme production. Amino acid data, obtained after treating keratin powder with the supernatant culture, suggest that the major free amino acids resulting from keratin degradation are phenylalanine, tyrosine and valine. In addition, native chicken feather was degraded completely at 20°C in 2.5 d by this bacterium.

Characterization of a new keratin-degrading bacterium isolated from deer fur

A keratin-degrading bacterium was isolated from soil containing deer fur. An axenic culture of the keratin-degrading bacterium was obtained in liquid culture using a keratin enrichment technique. The isolated bacterium was gram negative and catalase- and oxidase-positive. Transmission electron microscopic observations showed that the bacterium was rod-shaped, 1.0–1.3 μm long and 0.7 μm in diameter. Phylogenetic analysis of 16S rDNA revealed that the new isolate has only 90.6% homology with Stenotrophomonas nitritireducens. Hence, this new bacterium was designated as Stenotrophomonas sp. D-1. The optimum temperature was determined to be 20°C for maximum growth and keratinolytic enzyme production. Amino acid data, obtained after treating keratin powder with the supernatant culture, suggest that the major free amino acids resulting from keratin degradation are phenylalanine, tyrosine and valine. In addition, native chicken feather was degraded completely at 20°C in 2.5 d by this bacterium.

Submerged culture screening of two strains ofStreptomyces sp. with high keratinolytic activity

Keratinases can be used for the production of potentially important hydrolyzed proteins and chemicals. This study investigated the keratinolytic activity of Streptomyces sp on keratinaceous materials like wool. High levels of proteolytic and keratinolytic activity were obtained after 96 h of culture when two Streptomyces sp strains were grown on basal medium containing mineral salts and 3% (w/v) of defatted wool as a source of energy, carbon, and nitrogen. The cell-free culture filtrates exhibited rapid proteolytic digestion of keratin powder. Currently, the authors are testing whether the enzymatic activity obtained is in fact keratinolytic, and not only an alkaline protease activity.

Keratin degradation by Scytalidium species and Fusarium solani.

The keratin degradation capability of some non-dermatophytic filamentous fungi, viz Scytalidium dimidiatum types A and B, S. hyalinum, S. japonicum and Fusarium solani, was investigated using nail clippings and keratin powder as substrates. Representative isolates of the dermatophytes Trichophyton rubrum and T. mentagrophytes were also tested. The two morphological types of S. dimidiatum were almost equally effective in the degradation of substrates, 42-43% nail clippings and 24-26% keratin. Scytalidium hyalinum and S. japonicum degraded 40% and 38% of nail clippings respectively. Degradation of keratin was insignificant. In the case of F. solani, nail clippings were degraded 43% and keratin 20%. The dermatophytes caused much higher degradation of nail clippings (70-73%) and keratin (42-52%).

Adsorption of Cationic-Anionic Surfactants to Keratin Powder

The adsorption of a cationic-anionic surfactants mixed system on keratin powder was studied using keratin powder in place of hair. The anionic adsorption isotherm of anionic surfactant was of the Langmuir-type. Those of cationic surfactant and cationic-anionic surfactant mixed system showed irreversible adsorption owing to strong interaction with keratin powder. The extent of adsorption was maximum at molar ratio 7/3 of cationic/anionic surfactants. The kinetic frictional coefficient was least and interaction between surfactants and ovalbumin, weakest. That the cationic-anionic surfactants mixed system has the properties of nonionic surfactant in aqueous solution and that the monomer concentrations of cationics having strong irritation decrease may suffice as explanation for the above results.

オクタデシルトリメチルアンモニウムクロライド／Ｎ‐ラウロイル‐Ｎ‐メチル‐β‐アラニンナトリウム混合界面活性剤の蛋白質への吸着挙動

The adsorption of Octadecyltrimemmonuim chloride (C18 TAC)/Sodium-N-lauroyl-N-metyl-β-alanine (NaLMA) mixed system on keratin powder which was used as substitute for human hair was studied. The adsorption isotherm of C18 TAC showed irreversible adsorption, resulting in the decrease of the kinetic frictional coefficient compared to other cationic surfactants (C10TAC, C12TAC, C14TAC, C16TAC). The adsorption istherm of NaLMA was of the Langmuirtype, but those of C18TAC/MaLMA mixed system showed irreversible adsorption owing to strong interaction with keratin powder. The amount of adsorption was maximum at molar ratio 7/3 of C18TAC/NaLMA. At the same ratio, the kinetic frictional coefficient and denaturation rate showed minimum values. That the behavior of C18TAC/NaLMA mixed system is similar to nonionic surfactant aqueous solution and that the monomer concentrations of C18TAC having the strong interaction decrease by formation of ionic pair between C18TAC and MaLMA may suffice as explanation for the above results.

Adsorption of Cationic Surfactants to Keratin Powder

The adsorption of cationic surfactans onto keratin powder was studies to determine differences in alkyl chain length (C10C18). The adsorption isotherms of C10C14 cationics were of the Langmuir-type. Those of C16 and C18 cationics showed much stronger interaction with keratin powder than those of C10C14 cationics. Irreversible adsorption was also observed in the former. The kinetic frictional coefficient of keratin powder-adsorbed C10C18 cationics was measured. For C16 and C18 cationics, the values were less than those of C10C14 cationics. The amount of saturated adsorption, the sum of both hydrophobic and irreversible adsorption, increased in the order : C14>C16, C18>C12>C10.The antibacterial capacity of cationic surfactants against Staphylococcus aureus was assessed and interactions between cationic surfactants and ovalbumin were studied. The results in each case were found to be related to saturated adsorption. C14 showed the highest activity toward Staphylococcus aureus, ovalbumin and keratin powder regarless of the type of protein.