Quality properties of flax fibers retted with enzymes

Flax that has been mechanically treated in an opener-blender to disrupt stem integrity is enzymatically retted with a series of enzyme formulations with different levels of Flaxzyme with or without ethylenediamine-tetra-acetic acid (EDTA) as a chelator. Samples are then characterized by light and transmission electron microscopy and fiber tests for micronaire, strength (g/tex), and elongation. Unretted control fibers are off scale for micronaire and consist of fiber bundles with associated epidermis/cuticle fragments. Structurally, the lowest level of Flaxzyme used, i.e., 0.05% (w/v), plus 50 mmol EDTA produces ultimate fibers and bundles of various sizes without evidence of associated epidermis/cuticle. This formulation yields flax fibers with similar micronaire values and about 34% more strength than the recommended level of 0.3% Flaxzyme. A level of 3.0% Flaxzyme extensively removes middle lamellae from the bundles, produces the smallest micronaire values, and reduces strength to about 30% of fibers treated with 0.05% Flaxzyme plus chelator. Variations in fiber properties with the different formulations suggest that pectin degradation varies for different regions of the bast tissues and that specific strategies for improving enzymatic retting can be developed. Results show that fiber quality tests for cotton are useful in differentiating formulations for enzymatic retting of flax, and 0.05% Flaxzyme plus 50 mmol EDTA is the most efficient retting formulation.