Study on the action of endoglucanases in the production of nanocrystalline cellulose

Abstract

Nanocrystaline cellulose (CNC) is a nanomaterial with several applications, from the construction to the pharmaceutical sectors, and many others at developing potential applications. Currently, the process of CNC production involves the hydrolysis of cellulosic pulp (derived mainly from the kraft pulping, followed by the bleaching process) with concentrated sulfuric acid (approximately 65%). This is an inefficient (yields around 30%) and environmentally aggressive process, as large volumes of water are needed to remove the residual acid from the CNC. The objective of this work is to make use of the selectivity of endoglucanases, which hydrolyses mainly the amorphous regions of cellulose, to develop a novel process of CNC production, more efficient and environmentally friendly. Four families of endoglucanases with different specificity will be tested to hydrolyze the cellulosic pulp, in addition to their synergistic action with cellobiohydrolyses. In parallel, the conventional CNC production process will be conducted, as a control. In addition, an intermediate process, involving the enzymatic hydrolysis followed by a milder acid hydrolysis will be investigated. The three processes (acid; enzymatic; enzymatic + acid) will be compared based on the CNC production yield, volume of water needed in the washing step, as well on the morphological and physicochemical properties of the nanocrystals. By the end of the project, we hope to have determined the properties of an endoglucanase that are suitable for the CNC production process, in a more efficient and environmentally friendly way. (AU)