Modifying Dew - Retted Flax Fibers by Means of an Air - Atomized Enzyme Treatment

The use of atomization or an aerosol formation is investigated as a vehicle for enzyme treatment of dew-retted flax fibers. A cellulase/endoglucanase from Trichoderma reesei is applied by atomization to dew-retted fibers at concentrations of 0. 50, and 100 U. Enzyme activity post-atomization is verified by GLC analyses of sugars hydrolyzed from the treated fibers. Cellulase treatment results in the release of glucose and galactose moieties in a dose response manner. Fiber strength determination also demonstrates a dose response effect in relation to treatment with 50 and 100 U of enzyme, yielding strength decreases of 17 and 56%, respectively. Visualization of treated flax fibers by polarized light microscopy reveal the presence of structural aberrations previously identified as nodes, and treatment with the atomized enzyme coincides with fiber disruption at these regions. Mid-IR attenuated total reflectance spectra of fiber mats show a reduction in bound water and loss of acetylated components at the fiber surface resulting from enzyme treatment. Collectively. these results demonstrate the effectiveness of atomization as a means of applying enzymes for fiber modification, and the results also have implications for the flax fiber structure. Using pure enzymes or mixtures of enzymes to isolate bast fibers from flax stems is currently being investigated as a means to expand flax production and to improve flax fiber uniformity and efficiency of flax processing. Currently, dew retting is the predominant method of retting flax, particularly in Northern and Eastern Europe where the climatic conditions are conducive for producing high quality dew-retted fibers [II. 13. 26, 27, 30]. Enzyme retting, however, is independent of weather and would circumvent the ecological and, therefore. the geographical constraints required for dew retting. Enzyme retting could result in growth of the flax industry and expand production to the U.S. However, a commercially viable enzyme retting technique is not currently available, and while these technologies are being developed. dew-retted flax from Europe remains the primary source of fibers for textile applications. Dew-retted fibers result from the action of indigenous soil fungi, which colonize the harvested plant stems and degrade the pectic and hemicellulosic components of the stem through the action of extracellular polygalacturonases, xylanases, and arabinases [5, 6]. The degradation of these interstitial matrices results in the disassociation of fiber cells from their surrounding soft tissues, and subsequently allows for mechanical isolation of the cellulosic flax fibers by scutching and hackling [7, 12, 28. 29, 32~. Dew-retted flax fibers exhibit significant variations and are often coarse and of low quality [31 ]. Factors that may contribute to this lack of consistency include sporadic environmental conditions, inconsistent colonization by indigenous soil fungi, activity by cellulolytic organisms, and lack of an accurate means to determine the end point of retting 12, 19, 28, 29, 32]. The lack of consistency and quality in dew-retted fibers can affect downstream textile applications and the quality of the resulting product. This phenomenon is particularly apparent when dry spinning short stapled or &dquo;cottonized&dquo; flax fibers in blends with cotton. During this process, residual shive, cuticle. and surface waxes may limit interaction of fibers and thereby decrease spinning efficiency/production rate and reduce the strength of the resulting yarns [ 10]. 1~urthermore, the presence of these components can affect downstream processes such as bleaching and/or dyeing [ 18]. Research by Sharma indicated that treatment of flax roves with crude pectinolytic enzyme preparations to remove fiber contaminants enhanced the quality of resulting yarns [25]. In this work. enzymatic treatment consisted of submerging the roves at USDA, ARS, EASTERN REGIONAL RESEARCH CTR on June 25, 2009 http://trj.sagepub.com Downloaded from