Flax treatment with strategic enzyme combinations: Effect on chemical fiber composition and ease of fiber extraction

•Enzymatic treatment of flax offers a valuable alternative for dew retting.•Polygalacturonase combined with xylanase activity leads to a markedly chemical refining of flax fibers.•Enhanced fiber extraction efficiency reached by applying enzyme combinations.•Extraction efficiencies twice as high compared to green fibers by combining polygalacturonase and pectinmethylesterase. The effect of treatment of flax with strategic enzyme combinations on the ease of fiber extraction and the chemical fiber composition is reported in this study. To contribute to the increasing demand for bio-based and sustainable materials, it is of great importance to develop optimal enzyme formulations which can replace the yet poorly controlled traditional dew retting process. Regarding the chemical composition of the fiber, enzymatic treatments all resulted in similar improvements, with an enhanced cellulose content of 81 ± 1% after polygalacturonase + xylanase treatment (vs. 64 ± 2% for green fibers). Evaluation of extraction efficiency (EE) showed that several enzyme combinations significantly increased EE in comparison with green fibers. An EE of 23 ± 6% was found for fibers extracted after polygalacturonase + pectinmethylesterase treatment, in comparison with an EE of 11 ± 1% for green fibers. Combinations with three enzymes resulted in a higher reduction of the pectin content of the fibers. The combination of enzymes shows hence promising potential but further evaluation of mechanical performance of fiber reinforced composites is needed.