Comparative Analysis of Anaerobic Degumming Effects on Different Bast Fibers from the Angle of Enzyme Activity and Microbial Community Structure

Bast fiber textiles are becoming more and more popular, and degumming is a key process to obtain fiber. However, the more widely used degumming methods currently have a high level of pollution, which has become a primary problem restricting the development of the textile industry. Therefore, this study developed a continuous-flow anaerobic biological degumming system for bast fibers (Ramie and Hemp), with a self-developed spiral symmetry stream anaerobic bioreactor (SSSAB) as the core. The basic indicators of the degumming systems’ operation were analyzed, including pH, COD (Chemical Oxygen Demand), weight loss ratio, fineness, and breaking strength. pH and COD results indicated that the systems are operated continuously and steadily. The breaking strength of Ramie fiber and Hemp fiber were found about 4-6.5 cN/dtex and 2-4 cN/dtex, respectively, which meet subsequent spinning needs. The weight loss ratio of Ramie fiber (maximum value 27.27%) obtained by this anaerobic degumming method was generally higher than that produced by the traditional degumming method. SEM (Scanning Electron Microscopy) found the bast fibers current degumming time was too long and a lot of microorganisms adhered to the surface of the fibers. Enzyme activities testing in different fiber degumming systems found that the Ramie fiber degumming system has a higher cellulase activity than the Hemp fiber degumming system. From the perspective of community structure, it was believed that there were significant differences in microbial flora between Ramie and Hemp degumming systems, but there was no significant difference in archaea between them. This not only explored the adaptability of anaerobic continuous flow biological degumming system varieties but also provided theoretical guidance for enterprises to degum different bast fibers.