Improving microbial degumming efficiency for ramie fibers: Synergistic action of enhanced xylanase activity and...

Microbial degumming for producing ramie fiber has emerged as mainstream method owing to its eco-friendliness and low energy-consumption, however, its efficiency requires further improvement. This study proposed a synergistic approach to improve degumming efficiency by enhancing xylanase activity in Pectobacterium carotovorum HG-49 and optimizing pretreatment through ammonium oxalate soaking combined with microwave heating for ramie bast fibers. The pretreatment separated and dissolved most pectin, loosened the fiber structure, and provided ammonium oxalate as nitrogen source, thereby promoting HG-49 growth and enhancing its production of degradation enzymes. Therefore, the degumming time shortened by 2 h, the removal ratio of hemicellulose and total gum increased by 10.78% and 5.93%, respectively. The achieved gum removal rate of 87.33% within 14 h represents one of the highest values reported to date. This study demonstrated that synergistic action of enhanced xylanase activity and optimized pretreatment greatly improved the microbial degumming efficiency for ramie bast fibers.