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United States Department of Agriculture

Agricultural Research Service

Research Project: WOOL AND KERATIN FROM WOOL FOR BIO-BASED VALUE-ADDED PRODUCTS
2013 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:
Domestic wool is now recognized by the American Sheep Industry Association (ASI) as a valuable commodity for the production of novel keratin-derived products for niche-product development across a wide range of personal care, biomedical, pharmaceutical, and cosmetic industries. Publication, national and international presentations, formal agreements with industry partners and pending patent applications on ARS keratin products have led to the recognition that wool from the United States can hold a competitive edge against New Zealand wool, currently the keratin source is supplied as material additive to commercial personal care formulations. With the development of ARS keratin research, ASI stakeholders now have an outlet for all grades and quality of wool, whereas in the past wool fiber of poor grade with low quality was considered low-market-value waste. The wool industry has the potential to change with this technology. Wool and keratin extracted form wool as over 93% pure protein are investigated as stand-alone materials. Wool fiber is modified for strength improvement after processing by adding keratin. Wool fiber is imparted with antimicrobial resistance by attaching active agents through reaction mechanisms and through natural adhesion of keratin to keratinous materials. ARS Processing of wool continues sustained interest through co-investigations with on-going formal agreements, for example, an ongoing Agreement with Mori Consultant Eng, Japan, for modifications of the process for application to specific textile materials.

Characterization of new keratin products formed in various physical shapes were evaluated for moisture uptake and delivery as biobased model hydrogel systems with implications of the potential to deliver beneficial active agents to keratinous substrates for healing and therapy. ARS keratin materials and products are routinely evaluated for thermal and rheological properties to determine their suitability for particular end-uses.

New keratin hydrogel products formed by admixture with common food and agricultural materials were found to effectively transform keratin powder into gels, films, sponge, wet-spun strands, creams, and poultice. New keratin products were synthesized to replace silicon in commercial formulations. Modifications of these novel product were investigated to produce a broad spectrum of hydrated keratin materials of specific shape and thermal and mechanical behavior. In cooperation with investigators, formulations, characteristics, and rheology of keratin products were tailored to meet the requirements for particular end-uses. Keratin- thermally-responsive materials with intact functional groups and microstructure exhibited unique mechanical, rheological, and textural properties as stand-alone keratin products and as keratin adducts formed from keratin and modified keratin as reactive precursors.


4.Accomplishments
1. Keratin from wool has high-value market potential. At the request of ASI to utilize and evaluate fine- and coarse-grade wool as a source of keratin, various methods of extraction were applied to fine and coarse wool in side-by-side comparisons by ARS researchers at Wyndmoor, Pennsylvania. Product characterizations indicated that native chemical functions and microstructure of intact wool were preserved. Wool is “feedstock” for forming a broad array of keratin structural materials in different physical forms. Different ARS hydrolyses methods applied to extract keratin from wool provided a broad array of characteristically different keratin materials that are functional as stand-alone products and as co-additives. All keratin material forms proved tough, strong, and resilient. Instrumental methods of analysis showed that all were highly reactive as the commercial silicone replacements currently being incorporated into personal care products. This technology has the potential to change the wool industry. Keratin product development utilizes all wool fiber whereas only good-grad, long staple fiber is suitable for spinning to yarn.

2. Keratin biomaterials are to replace synthetic counterparts. New keratin products were developed, by ARS researchers at Wyndmoor, Pennylvania, from hydrolysate and powder with or without modification by chemical synthesis or admixture with natural ingredients, commonly accepted in the food and personal care industries. Providing a niche market for domestic wool in creating keratin-derived products as bio-based replacements for petroleum–derived materials such as silicones. All were characterized as hydrogels with the capacity to absorb up to 140% by weight of moisture. Keratin films, when partially or fully hydrated convert to creams, emollients, gels, sponges, poultice, and wet-spun strands, are functional,beneficial platforms as stand-alone materials or as co-additives to commercial formulations for particular end-uses in biomedical, pharmaceutical, personal care, and cosmetic industries. Product potential was thoroughly examined by applying in vitro studies for the uptake and release of active agents for therapeutic delivery of pharmaceuticals and for beneficial delivery of beauty and personal care ingredients. Three MTA Exchange Agreements with global industrial partners, keratin materials were distributed as powder and as dry film with instructions for hydration to the particular product forms dictated by specific end-use.


Review Publications
Cardamone, J.M., Tunick, M.H., Onwulata, C.I. 2013. Keratin sponge/hydrogel part 1. fabrication and characterization. Textile Research Journal. 83(7):661-670.

Cardamone, J.M. 2013. Keratin sponge/hydrogel II, active agent delivery. Textile Research Journal. 83(9):917-927.

Last Modified: 10/24/2014
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