Screening and identification of pectinolytic bacteria for ramie degumming

To explore high-quality microbial resources with the capability of ramie degumming, we collected soil samples from rotten ramie and straw heaps. After enrichment culture by ramie raw materials, bacterial strains with the potential ramie-degumming function were screened using a pectin-hydrolysis plate. Dominant bacteria were identified by combining colonial morphological characteristics with the molecular biology method, and their ramie-degumming effects were verified through comprehensive biological degumming indices. Results demonstrated that Bacillus aryabhattai, Bacillus thuringiensis, Lysinibacillus fusiformis, and Acidovorax temperans were successfully obtained. The highest pectinase activity, 98.2 U/mg, was found by A. temperans. B. thuringiensis showed the best ramie-degumming effect. The residual gum content, single-fiber linear density, and bundle-breaking strength of the degummed ramie fiber treated with B. thuringiensis were 8.32%, 6.80 dtex, and 7.84 cN/dtex, respectively. The residual gum content of the ramie fiber treated with B. thuringiensis met the textile requirement (<10%), and the values of all other indicators were also satisfactory. Therefore, B. thuringiensis was an excellent strain for ramie degumming, indicating potential industrial applications.