Flax-retting by polygalacturonase-containing enzyme mixtures and effects on fiber properties.

Enzyme-retting of flax was accomplished via individual treatment with four polygalacturonase (PGase) containing solutions of various fungal sources and the resulting fibers were characterized. The retting solutions were equilibrated to contain 2.19 U of PGase activity as determined via a dinitrosalicylic acid (DNS) reducing sugar assay. As compared with the buffer control, treatment with the various enzyme solutions increased the yield of fine fibers. Treatment with Aspergillus niger PGase resulted in a 62% increase in fine fiber yield as compared with 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. These results illustrate that the crude PGases differ in their ability to ret flax and that under the defined experimental conditions the A. niger PGase is a better retting agent. 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. Activity against carboxymethyl cellulose (CMC) was a minor component of all solutions except A. niger PGase for which no activity was detected.