Production of efficient enzymes for flax retting by solid state fermentation with Aspergillus niger

摘要

Purpose - The purpose of this paper is to study the optimum culture condition of flax-retting enzyme, and applying the enzyme liquors to retting. In addition to research the structure of flax stem in enzyme retting using scanning electron microscopy (SEM). Design/methodology/approach - The influence of cultural parameters such as moisture level, temperature, incubation time and inoculum size were evaluated with respect to polygalacturonase and xylanase yield. The structure of flax stem was revealed by SEM. Findings - The flax was retted by dilute enzyme liquors (polygalacturonase/25 U/ml, xylanase/1 U/ml), and 24-h retting period was obtained. The SEM studies revealed the removal of a large amount of non-cellulosic gummy material of flax stem in enzyme retting. Originality/value - First, flax-retting enzyme containing higher-yield polygalacturonase, lower-yield xylanase and no cellulose was yielded by SSF. Second, the composition of enzyme could meet flax retting and no damage cellulosic fibre. Finally, only low-cost wheat bran, citrus peel powder and mineral salt were employed in substrate, which could reduce the overall cost of enzyme production and flax retting.