Avaliação do potencial da casca de mandioca para aplicações em processos biotecnológicos.

Abstract

With the urban-industrial development and the increase of the population, there was a significant growth in the demand for energy sources. As a result, the generation of waste gradually increased, associated with waste in the use of inputs, losses between production and consumption and the materials that are generated along the agro-industrial production chain. In this sense, the search for alternative and renewable sources, capable of minimizing environmental impacts and diversifying the energy matrix, has increased. As a result, lignocellulosic biomass is gaining prominence for being a renewable and abundant source. Currently, several types of pre-treatments have been studied to reduce the recalcitrance of lignocellulosic biomass in order to increase its chemical / enzymatic digestibility, so that it can be used in the production of ethanol and / or other value-added bioproducts. The present study aimed to assess the applicability of biomass from the processing of cassava roots (Manihot esculenta Crantz) (bark), as a potential raw material in the generation of chemical and / or biofuels products, through its characterization. In addition, perform a pre-treatment step, to make part of the sugars present in the holocellulosic fraction available and reduce the recalcitrance of the material. Initially, moisture, ash, extractives, lignin and holocellulose (cellulose + hemicellulose) contents were determined, in addition to the amount of reducing sugars by the DNS method (3,5-Dinitrosalicylic acid). Subsequently, a hydrothermal pretreatment test was carried out, catalyzed by bentonite clay activated with sulfuric acid. The tests were conducted in an autoclave at 120 ° C, with and without catalyst. The experiments followed the conditions established in a 2² factorial design with three repetitions at the central point, to assess the influence of reaction time and catalyst mass on the amount of reducing sugars (AR) present in the reaction medium. From the results, referring to the characterization, the result obtained for holocellulose stands out, being possible to verify a content above 70%, which is considered significant, enabling biomass as a potential raw material for several bioprocesses, aiming to obtain products with high added value. Low levels of moisture, lignin, ash and extracts were observed, with the results being, respectively, 2.32%, 7.91%, 4.02% and 6.16%. In connection with the pre-treatment stage, the best results were obtained for a 180-minute time and a 5.0 g clay mass, with 59.33 mg.mL-1 of AR being observed, indicating that acidified bentonite has activity catalytic. However, the statistical analysis showed that, for a 95% confidence level, none of the factors has a significant effect on the amount of RA generated. Thus, it was found that the studied material can be applied in bioprocesses that will allow obtaining chemicals and biofuels with high added value, showing the richness present in residues that most of the time are disposed of inappropriately.