Submitted to: Journal of Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/27/2002
Publication Date: 5/15/2002
Citation: Evans, J.D., Akin, D.E., Foulk, J.A. 2002. Flax-retting by polygalacturonase-containing enzyme mixtures and effects on fiber properties. Journal of Biotechnology; Vol. 97, pp. 223-231. Interpretive Summary: Among the obstacles currently faced by a fledgling flax/linen industry in the US is the difficulty in removing the cellulosic fibers from their resident stems. These fibers may be freed by treatment with enzymes which degrade the adhesive components of the flax stem. During this process termed enzyme retting, fiber quality may also be affected. Results of this sstudy demonstrate that a particular enzyme mixture produced higher yields of higher quality fibers. Evidence is also provided as to the importance of utilizing enzyme solutions free of fiber-degrading enzymes. This study provides more information necessary to optimize enzyme retting of flax which is fundamental in establishing a flax industry in the US.
Technical Abstract: Enzyme retting was accomplished via treatment with four polygalacturonase- containing solutions of various sources. Each retting solution was equated to contain 2.19 U of polygalacturonase (PGase) activity as determined via a dinitrosalicyclic acid reducing sugar assay. As compared to the buffer control, treatment with the various enzyme solutions increased the yield of ffine fibers. Treatment with Aspergillus niger PGase resulted in a 62% increase in fine fiber yield as compared to the buffer control and fiber strength did not statistically differ (p<=0.05) between these treatments. Retting via PGases of Rhizopus origin produced the weakest fibers. Under the defined experimental conditions, A. niger PGase was a better retting agent than the other enzyme solutions tested. Light microscopy demonstrated the ability of all enzymes to separate fiber from shive and epidermal tissues. Enzyme profiles of the solutions were determined via viscometric assays. Pectinolytic activity was the predominant activity of all enzymes tested. To various degrees, the enzymatic solutions also catalyzed the degradation of highly esterified pectin (÷90% esterified) and xylan. Activity against carboxymethyl cellulose (CMC) was a minor component of all solutions except A. niger PGase for which no activity was detected.