The role of non-glucose residues in determining the crystallinity of native cellulose

Abstract

Industrial production of ramie fibers by chemical degumming results in problems such as environmental pollution and inferior fiber quality, which are unsustainable and hinder the development of relevant industries. For these reasons, an in-situ microbial degumming process with direct application of Bacillus sp. HG-28 was developed and presented here to solve these problems. This strain was selected for its high degumming ability and low cellulose damage. In the degumming process, the gum in ramie bast fibers induced the strain to secrete high activities of pectinase and xylanase, both of which were proven to be essential for degumming. After 16 h of degumming, gum content reduction was measured to be 76.92% while cellulose loss could not be evidently detected. This is more efficient than other reported microbial degumming methods that do not use microorganisms directly. According to the results of in-situ microbial degumming in industrial scale, the residual gum content of degummed ramie fibers decreased to 1.81%, the bundle breaking tenacity reached 5.09 cN/dtex and, additionally, the consumption of chemicals, water and energy were significantly reduced, proving superior to chemical process. This study provides a sustainable alternative for the conventional chemical degumming industry.