Optimization of an enzymatic cocktail for obtaining cellulose nanofibers

Abstract

Earth’s resources are getting exhausted, and thus, some alternatives are being contemplated to raw materials traditionally used; one of these alternatives are cellulose nanofibers. One of the pretreatments applied to cellulose fibers consists in enzymatic hydrolysis. This study expects to accomplish the optimization of an enzymatic cocktail with the aim of making the process more efficient, emphasizing the fact that it goes in tune with green chemistry. The established objectives consist on determine the unknown components, obtaining them separately, and assay different combinations in order to optimize the enzymatic cocktail avoiding antagonisms and promoting synergisms. In the present study, the laboratory has been able to know the two main enzymes of the cocktail, and nanofibers have been obtained applying different combinations and enzymatic proportions. Then, nanofibers have been characterized in terms of: nanofibrillation yield, transmittance, carboxyl content, cationic demand, specific surface and diameter. Moreover, it has been tried to produce hydrogels with nanofibers obtained applying the commercial treatment, since these nanofibers have shown greatest characteristics. Therefore, the principal objective consisting on optimizing the enzymatic cocktail has not been accomplished. Despite nanofibers obtained applying the commercial cocktail have been the ones that have stand out when it comes to characterization, they still are away from the values achieved when a TEMPO-mediated oxidation treatment is applied. Based on this fact, some hypotheses have arisen, these include the fact that maybe there is another key enzyme, or the possibility that the enzymatic proportions facilitated by the commercial company were distorted. These unsatisfactory values have been reflected when producing hydrogels, since they rapidly disintegrated when were submerged in water. The explanation consequently generated, resides in the fact that enzymatic nanofibers present low carboxyl content, and thus, the crosslinking reaction with citric acid, that allows obtaining hydrogels, is not favored. Therefore, it is seen that there is still a long way to go when it comes to enzymatic studies for nanofiber’s obtaining and its applications. In this work, some possible lines for future studies are traced