Enzymatic extract of Aspergillus fumigatus CCT 7873 for hydrolysis of sugarcane bagasse and generation of cellulose nanocrystals (CNC)

Abstract

In this study, cellulose nanocrystals (CNC) were produced from untreated and pretreated sugarcane fibers through enzymatic hydrolysis using a crude cellulolytic extract produced by the fungus Aspergillus fumigatus CCT 7873 using semi-solid fermentation (SSF). The fibers were characterized in terms of cellulose, hemicellulose, and lignin contents and crystallinity index. The CNC generated during the enzymatic hydrolysis using a sugarcane fiber pretreated with 4% NaOH and an enzymatic loading of 7.5 FPU g−1 of bagasse were characterized by atomic force microscopy (AFM). The results showed that after the hydrolysis time of 48 h, spherical-like particles with a good size distribution and a mean diameter of 61 nm were obtained. In this study, we produced cellulose nanocrystals (CNC) from untreated and pretreated sugarcane fibers through enzymatic hydrolysis using a crude cellulolytic extract produced by the fungus Aspergillus fumigatus CCT 7873 using semi-solid fermentation (SSF). In fact, the main novelty of this manuscript is the fact that it accompanies the formation of CNC, by means of atomic force microscopy (AFM). It is noteworthy that there are few manuscripts with this approach in the literature. In addition, this was performed during the cultivation of a fermentation broth containing cellulases produced by an enzymatic extract of the fungus Aspergillus fumigatus CCT 7873 using SSF. Thus, CNC, a highly added value product, can be obtained from lignocellulosic residues, which is a renewable and low-cost source. The results showed that, during the cultivation, there is a variation in the size distribution of the CNC and that, for the hydrolysis time of 48 h, a good size distribution was obtained for the CNC with about 61 nm in diameter, presenting a spherical shape.