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United States Department of Agriculture

Agricultural Research Service

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Location: Biobased and Other Animal Co-products Research

2011 Annual Report

1a. Objectives (from AD-416)
Develop commercially viable processes based on chemical or enzymatic crosslinking that increase the market value of wool. 1A: Develop systems for functional modification of wool. 1B: Develop keratin modification systems. Develop extraction and derivatization processes for the production of commercially viable products from keratin. 2A: Extract and characterize keratin from wool. 2B: Form structural keratin materials for product development.

1b. Approach (from AD-416)
1A. Crosslinking and self-crosslinking systems can be used to modify wool. - Wool fabric of fine-gauge jersey knit suitable for military underwear will be processed by the ARS Process to confer anionic charge for subsequent reactivity with quaternary amine compounds to add antimicrobial resistance. This approach can be used to attach other compounds containing quaternary amino groups. It will also be used to improve physical/mechanical properties. 1B. Keratin can be self-crosslinked, crosslinked to wool, and crosslinked to agents for delivery to wool through TG-mediation. - How to retain or increase the strength of wool in processing will be addressed by applying KP with and without TG to a fine-gauge jersey fabric of fine yarn size required by Military specifications for ARS washable wool. The extracted keratins of domestic wool from fine to coarse will be applied to the fabrics. Their adhesion and permeation characteristics will be examined. The effects of these applications on strength, shrinkage and physical/mechanical properties will be determined. Making these applications to the fabric will enable the determination of how the various KP molecular weight fractions impact fiber strength and this will have implications for yarn processing before the fabric is knitted or woven. 2A. Oxidation, reduction, and enzyme systems can be used to isolate keratin with the chemical and structural integrity of wool. - Alkaline oxidation and reduction methods will be used to hydrolyze wool to convert keratin amides and disulfides to the corresponding acids. Smaller peptide and protein fragments from hydrolysis of wool will be composed of Type II keratin intermediate filament and keratin with microfibrillar structure. MALDI-TOF/TOF spectrophotometry will be used to identify these IFPs. Keratin functionality and end-use will be determined by the hydrolysis conditions used to break or restore disulfide likages. KP sites of reactivity such as amide, carboxyl, sulfoxide, sulfide, and thiosulfide will be identified. Solubilized wool fiber with will exhibit various transformed morphologies such as lyophilized powders. The isolated keratin materials will be characterized by molecular mass and functional group content to determine their unique characteristics as feedstock materials for developing novel products and applications. Hydrolysis systems will be designed to recover pure keratin in the form of IFPs as constituent microfibrillar and matrix proteins. The conditions of hydrolysis will range from mild to severe as governed by pH, exposure time, and temperature. One method will involve alkaline oxidation hydrolysis at pH 12 to 13. 2B. Keratin from wool can be tailored into adaptable forms which can be modified to meet the needs of bio-based commercial markets to replace petroleum-derived products. The physical forms and behaviors of these products will be controlled by the conditions of wool hydrolysis, keratin recovery from hydrolysis, and subsequent modification (s) of the extracted keratin.

3. Progress Report
This is the first full-year report for the new wool project with objectives to improve the value of domestic wool by improving properties through physical and chemical modification, to develop keratin-from-wool technology to position wool in new and niche markets for high technological development of products for the hair, skin, and biomedical, pharmaceutical, and cosmetic industries. Modification of wool and keratin-from-wool, to improve properties and impart functionality for improved performance, open new markets to expand the uses of domestic wool. The following fall within NP306 Plan Component 2 (Fibers) Problem 2A (Define, Measure, and Preserve Quality) and Problem 2B (New or Improved Technologies, Processes, or Products) 1a. Systems for functional modification of wool: the utility of patented and licensed ARS Process for wool bleaching, biopolishing, and shrinkproof was further investigated to apply to wool blended with other fiber types and to create a new wool fabric type with open structure and stiffness suitable for new end uses. The adhesion of keratin to keratinous substrates was further examined and extended to investigate the physical adhesion of binding keratin materials together and to wool. 1b. Enzyme-assisted crosslinking was further investigated and extended to investigate the binding of keratin to keratin, keratin to wool, and keratin-associated nanoparticles to wool. Based on positive results other chemical reactants with the salient functions required for transamidation crosslinking to keratin and to wool and to keratin-associated-wool, were identified for adding greater value to these constituents. 2a. Hydrolysis systems were designed to yield new keratin materials with different characteristics and functional groups. Alkaline hydrolysis, oxidative hydrolysis, and reduction hydrolysis and other various recovery methods were designed to produce keratin materials within a broad molecular weight range: 4-6kDa (keratin peptide) to 40-60 kDa (keratin protein). These keratin isolates were characterized by wet-chemical analysis and instrumental analysis, which showed that the keratin materials consist of a broad range of functionalities. This work continues to progress under a Material Transfer and Cooperative R&D Agreement with a global chemical company to derive innovative products from renewable natural raw materials to meet specific end-uses. 2b. Keratin isolates from the individual hydrolysis methods were isolated as keratin films, gels, sponges, mats, microfibers and were evaluated for their native potential as stand-alone products and as adducts to meet targeted end-uses. Keratin hydrolysates and powders were chemically modified for the product development of keratin elastomer materials. Various recovery methods were developed to yield keratin hydrolysates as starting materials for the formation of keratin wet spun fibers. The recovered keratin hydrolysates were chemically modified by changes in acidity/ basicity to obtain solid fractions of keratin. These solid fractions were used as starting materials for wet spinning experiments to obtain keratin fibers of discrete fiber diameter and flexibility.

4. Accomplishments

Review Publications
Cardamone, J.M. 2011. Expanding the utility of the Agricultural Research Service (ARS) process bleaching. Textile Research Journal. 81(17):1818-1827.

Martin, J.J., Cardamone, J.M., Irwin, P.L., Brown, E.M. 2011. Keratin capped silver nanoparticles - synthesis and characterization of a nanomaterial with desirable handling properties. Colloids and Surfaces B: Biointerfaces. 88(1):354-361.

Last Modified: 10/17/2017
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