Comparison of the surface constitutions of hemicelluloses on lignocellulosic nanofibers prepared from softwood and hardwood

Abstract

Lignocellulose nanofibers (LCNFs) were directly prepared from the wood powders of softwood from cryptomeria and hardwood from eucalyptus, and differences in the surface constitutions of the prepared LCNFs were studied via quartz crystal microbalance (QCM). QCM analyses indicated different results in the enzymatic hydrolysis of these LCNFs with a multicomponent cellulase mixture in the initial stage of the reaction, suggesting that LCNFs prepared from cryptomeria and eucalyptus had different surface constitutions. A QCM analysis of the enzymatic hydrolysis of LCNFs with a multicomponent cellulase mixture after individual treatments with xylanase and mannanase were also conducted, where the results suggested differences in the laminated structure of hemicelluloses located around the cellulose microfibrils composing the LCNFs of cryptomeria and eucalyptus. According to the QCM results, the cellulose microfibrils composing LCNFs prepared from the softwood of cryptomeria are likely integrally surrounded by glucomannan, meanwhile the cellulose microfibrils composing the LCNFs prepared from the hardwood of eucalyptus exhibited low numbers of hemicelluloses surrounding the cellulose microfibrils, where a portion of the surface of the cellulose microfibrils is likely to be exposed.