|Rigsby, Luanne - Lowe|
Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/7/1997
Publication Date: N/A
Interpretive Summary: The critical process in extracting textile and industrial fibers from bast plants is retting, which is a microbial action where selected plant components are degraded to isolate the cellulosic fibers. Current retting methods are inadequate to produce consistent fibers of high quality that are needed to help establish a flax fiber industry in the US. Research at the Russell Research Center showed that previously unknown fungi from dew-retted flax were good sources of enzymes for an improved process of enzymatic-retting to produce high quality fibers of consistent quality. Results are significant in that they show that newly discovered microorganisms could form the basis for new methods of retting flax to help establish the newly emerging US flax fiber industry.
Technical Abstract: Seven strains of filamentous fungi are one yeast were isolated from flax that was dew-retted in the US. The filamentous fungi were subcultured to purity and identified, and six appear not to have been reported earlier as isolates from dew-retted flax. Five of the purified US strains, two fungi isolated from flax dew-retted in Europe, and a laboratory culture of Aspergillus sojae were tested for their ability to ret flax stems. The monocultures were evaluated for the degree of retting, fiber strength, dry weight loss, and tactile response (i.e., feel of softness) as reflected in the retted fiber. Structural modifications of representative samples of the retted flax were assessed by scanning electron microscopy. All the filamentous fungi were able to carry out some retting, whereas the isolated yeast could not. All organisms produced pectinases when cultivated in shake flasks on ball-milled flax as sole carbon source. Some fungi also produced cellulases, mannanases and xylanases. Rhizomucor pusillus and Fusarium lateritium were noteworthy as retting organisms by their high pectinase activity, ability to attach non-cellulosic cell types without attacking cellulose, capacity to penetrate the cuticular surface of the stem, and their efficient fiber release from the core. The results indicated that these organisms deserve further study as potential organisms for retting of bast fibers in industrial applications.