Extraction and characterization of corn husk fibers using Aspergillus niger fermentation

Purpose This study aims to develop an effective and relatively mild biological degumming process for extracting corn husk fibers using Aspergillus niger fermentation after low-concentration alkali pretreatment. The study also evaluates the potential of the extracted fibers for textile intermediates, nonwovens and bio-based composite applications. Design/methodology/approach Corn husks were pretreated with a low-concentration alkaline solution and then degummed by Aspergillus niger fermentation. The fermentation conditions were optimized using single-factor and orthogonal experiments. Weight loss rate and residual gum content were used as the main evaluation indices. The extracted fibers were characterized by chemical composition analysis, optical microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, tensile testing and sensory evaluation. Findings The optimized fermentation conditions were pH 5.0, 32 °C and 96 h. Under these conditions, the weight loss rate and residual gum content were 58.43% and 43.01%, respectively. Fermentation effectively removed part of the non-cellulosic gummy substances, particularly hemicellulose and lignin, improved fiber separation and reduced interfiber adhesion. The extracted fibers showed a pale-yellow appearance, soft handle and a breaking strength of 19.52 cN. Structural analyses confirmed that the cellulose crystal form remained as cellulose I after treatment. The increase in crystallinity index was mainly related to the removal of amorphous non-cellulosic components and was associated with improved thermal stability. Research limitations/implications This study was conducted at laboratory scale. Further work is needed to evaluate pilot-scale operation, process stability, water and energy consumption, downstream fiber processing and techno-economic feasibility. Originality/value This study provides a mild route for valorising corn husk, an underused agricultural residue, through combined alkali pretreatment and Aspergillus niger fermentation. Unlike many previous studies that focused mainly on chemical extraction or composite reinforcement, this work links fermentation degumming with residual gum content, fiber separation, handle and potential textile processability.