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United States Department of Agriculture

Agricultural Research Service


Location: Quality and Safety Assessment Research Unit

2007 Annual Report

1a.Objectives (from AD-416)
Enhancing value of fiber commodities, such as industrial fibers kenaf, flax, and cotton, through microbial and enzymatic activities. Design, develop, and test specific woven and non-woven materials for composites with specific properties and industrial applications. Specifically,.
1)optimize retting methods for separating high and consistent quality fibers from both seed- and fiber-type flax cultivars,.
2)develop standard methods and practices through established subcommittee D 13.17 of ASTM to objectively measure fiber properties,.
3)through ARS-USDA, governmental, and industrial collaborations, design and produce woven and non-woven flax fiber products for construction of composites for specific industrial applications.

1b.Approach (from AD-416)
Develop composites from flax fiber. Agricultural crops and products will be treated with microorganisms and enzymes that selectively remove fiber components and enhance value of products and processing methods. Treatments will be selected from available commercial enzymes and from newly isolated microorganisms and newly developed enzyme mixtures. Work will focus on improving retting procedures for obtaining fibers from bast plants such as kenaf and flax using enzyme mixtures containing pectinases, hemicellulases, and other non-cellulase enzymes that facilitate fiber separation from stems. Successful efforts at retting will be followed with research to scale up the process and work towards developing a commercial process for enzyme retting of bast fibers. Physical, chemical, and structural properties of treated fibers will be characterized by modern methods, and a body of knowledge will be developed to establish standards for evaluating fiber and fiber processing. New methods will be developed for rapid determination and evaluation of these standards.

3.Progress Report
Research on flax continued on testing optimal conditions for retting with specific pectinases that maintain strength and cleanliness. Specific protocols were established for order and conditions to optimize retting. New work was initiated on an enzyme, Inotex SER-3, with reported retting activity in the field and which would augment dew-retting in the field. Tests included: Frieds Test, free-hand cross sections, and laboratory and in-field large lots of fibers. Development of flax standards continued to include linseed shive and cuticle as contaminants and with prediction of bast fiber in intact plants. The prediction model for shive was tailored more to linseed cultivars (main ones in the US and Canada). Work was continued on new standards, dealing with cuticle fragments associated with fiber and bast fiber content. Work was begun on separating and evaluating wax from the plant cuticle for policosinol-like profiles. Work was continued on lipid and aromatic constituents of shive waste fractions for co-products. Preliminary work was carried out on extraction and determination of components, and the lignin-like fractions were identified and quantitated. Work continued on pretreatment of lignocellulosic materials for co-products from potential bioenergy sources. Corn fiber and a series of grasses pretreated with specific commercial esterases prior to incubation with cellulase and showed a significant increase in fermentable sugars and phenolic acids, which could serve as potential high-value co-products. Milling for finer particles further increased the release of sugars and aromatics. Subordinate Projects: Through SCA # 5-6612-3-0237 flax fibers as well as non-woven mats made with flax fiber and flax/cotton blends were tested with new software on the Instron for strength and thickness by ASTM and AATCC standard test methods. Mats were further evaluated for filtration uses This SCA ended this year. The final report was approved and budgetary information passed along to the Contracts Officer. Through another SCA # 5-6612-3-0238 additional samples of enzyme-retted and dew-retted flax were processed through both the Unified Line and secondary cleaning stages of the pilot plant at ARS-Clemson. Assessment was made of the fiber yield and quality from large scale retting trials and with samples from commercial operations in North America. Incubation vessels and spraying devices were further developed and tested. Results showed that clean, high quality fiber could be obtained from linseed straw by dew-retting and enzyme-retting and a commercial “tow” fiber could be upgraded for a clean fiber for higher-value composites. With enzyme retting developed to pilot plant level, strategies were outlined and discussed for future development of commercial systems. The project will end this fiscal year. Both SCAs were monitored the ADODR with frequent meetings and frequent phone calls. Frequent joint travel occurred to off-sites where flax was grown or processed.

Title: On-line sensing of flax processed through a commercial system. Flax fibers are mixed with various levels of shive (woody, core cells comprising a fraction of the stem) that affect quality and subsequent use of the processed fibers. To expand markets for flax fiber, a quick and non-destructive method is needed to assess fiber cleanliness on-line and also assess the final product. Selected commercial bales of flax tow were monitored using a hand-held spectrometer containing a shive prediction model we developed earlier. Monitoring was at various positions in the processing system and for final products that have been subjected to various protocols. Data predicted shive levels at various stages and for fibers from specific, predetermined protocols comprising a test set. The impact for this accomplishment is the use of a cleanliness standard to characterize fibers for various applications. Such fibers matched with applications will begin to build a grading system for natural fibers that currently does not exist and that limits the markets of of flax and other bast fibers. This accomplishment addresses 306 N Quality and Utilization of Agricultural Products and the Research Component “New Processes, New Uses, and Value-Added Foods and Biobased Products” and Problem Area 2c. “New and Improved Processes and Feedstocks”.

5.Significant Activities that Support Special Target Populations

6.Technology Transfer

Number of non-peer reviewed presentations and proceedings4

Review Publications
Akin, D.E., Condon, B.D., Sohn, M., Foulk, J.A., Dodd, R.B., Rigsby, L.L. 2007. Optimization for enzyme retting of flax with pectate lyase. Industrial Crops and Products. 25:136-146.

Akin, D.E. 2007. Grass lignocellulose: strategies to overcome recalcitrance. Applied Biochemistry and Biotechnology. 136-140:3-15. 2007.

Marshall, W.E., Akin, D.E., Wartelle, L.H., Annis, P.A. 2007. Citric acid treatment of flax, cotton and blended nonwoven mats for copper ion absorption. Industrial Crops and Products. 26:8-13

Marshall, W.E., Wartelle, L.H., Akin, D.E. 2007. Flax shive as a source of activated carbon for metals remediaton. BioResources 2:82-90.

Last Modified: 4/16/2014
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