Improved properties of micronized genetically modified flax fibers.

The aim of this study was to investigate the effect of micronization on the compound content, crystalline structure and physicochemical properties of fiber from genetically modified (GM) flax. The GM flax was transformed with three bacterial (Ralstonia eutropha) genes coding for enzymes of polyhydroxybutyrate (PHB) synthesis and under the control of the vascular bundle promoter. The modification resulted in fibers containing the 3-hydroxybutyrate polymer bound to cellulose via hydrogen and ester bonds and antioxidant compounds (phenolic acids, vanillin, vitexin, etc.). The fibers appeared to have a significantly decreased particle size after 20h of ball-milling treatment. Micronized fibers showed reduced phenolic contents and antioxidant capacity compared to the results for untreated fibers. An increased level of PHB was also detected. Micronization introduces structural changes in fiber constituents (cellulose, hemicellulose, pectin, lignin, PHB) and micronized fibers exhibit more functional groups (hydroxyl, carboxyl) derived from those constituents. It is thus concluded that micronization treatments improve the functional properties of the fiber components.