The bagasse of Agave tequilana Weber is one of the most abundant agroindustrial wastes in the state of Jalisco. However, at the present time, there is no technical use for this waste, and its high availability makes it an environmental problem. The objective of this research was to take advantage of this waste and give it an added value to be used in the elaboration of advanced materials. In this sense, the agave bagasse cellulose was obtained using an organosolv method. To obtain the nanofibrils, the cellulose was passed through 6 cycles of a microfluidizer. The material was classified by FTIR, confirming the presence of the functional groups (O-H, C-H, C-C, and C-O-C), characteristics of cellulose, and the elimination of hemicellulose and lignin present in agave bagasse without treatment. The X-ray diffraction technique allowed the determination of the degree of crystallinity of the cellulose nanofibers, which was 68.5%, with a negative zeta potential of −42 mV. The images from the atomic force microscopy helped for the observation of the degree of fibrillation in the cellulose, and with the software ImageJ, the average diameter of the nanofibers was determined to be 75 ± 5 nm with a relatively uniform length of 1.0–1.2 μm. Finally, by means of thermogravimetric analysis, it was found that the obtained cellulose nanofibers (CNFs) supported high temperatures of thermal decomposition, so it was concluded that due to the diameter of the fibrils, the high resistance to pressure, and elasticity, the nanofibrils obtained in this investigation can be used in the elaboration of advanced materials.

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The pineapple fruit when harvested generates a large amount of residual biomass; this biomass can be used to generate value-added products such as cellulose nanofibers. This study was focused on the isolation of CNF from pineapple leaves after oxidation pretreatment with 2,2,6,6-tetramethylpireridine-1-oxyl, followed by mechanical deconstruction of the fibers via combination of grinding and microfluidization process. One and two microfluidization passes were applied to bleached and unbleached fibers, respectively. The implications of these findings are that during the production process it is possible to reduce the amount of chemicals needed for bleaching and the energy involved in the mechanical microfluidization process. Such process yielded corresponding fibril lengths and widths in the range of 481–746 nm and 16–48 nm. The respective electrostatic charges, as measured by zeta potentials, were −41 mV and −31 mV. As expected, the CNF crystallinity was higher than that of the starting material, especially for the cellulose. However, the thermal stability was reduced, showing two degradative processes due to the chemical modification of the fibers. The CNF produced from pineapple leaves has a potential to be used like biomaterial in diverse applications while representing a viable alternative to producers, which face serious environmental and health challenges given the large volume of biomass that is otherwise left in the fields as waste. Graphic Abstract

O ensino de um modo geral tem sofrido inúmeras modificações ao longo dos últimos anos, principalmente em decorrência da introdução massiva do uso das tecnologias digitais no cotidiano das pessoas. Isto levou as instituições de ensino a criarem situações que incorporem essas tecnologias no proceso de ensino e aprendizagem. Nesse contexto, o objetivo desse trabalho é discutir a importância de abordar a inserção das tecnologias digitais no ensino. A utilização das TD nas aulas podem auxiliar os pofessores a tornar o ensino mais contemporâneo e interesante, e fazendo com que os alunos sejam mais responsáveis pelo seu proceso de ensino e aprendizagem.

En este estudio se prepararon y caracterizaron microcápsulas híbridas del conjugado de polifenoles derivados de la lignina proveniente de la cáscara de piña, y el quitosano obtenido a partir de la quitina de la cáscara del camarón; ambos materiales fueron obtenidos como residuos de la industria agropecuaria y pesquería de camarón de Costa Rica. Con el objetivo de preparar compuestos fenólicos derivados de la lignina, y utilizarlos en la síntesis de las microcápsulas, se realizó la hidrólisis enzimática de la misma en un reactor a presión atmosférica a un pH de 6.8, en buffer de citrato 1 M, durante 6 h a 37ºC. Las enzimas utilizadas fueron extraídas de los cultivos de hongos de Gloeophyllum trabeum (Pers.) Murrill y Phanerochae chrysosporiumin Burdsall. Para la obtención del quitosano desacetilación alcalina a partir de exoesqueletos del camarón Heterocarpus vicarius Fazon. Para la preparación de las microcápsulas se empleó una disolución de quitosano en ácido acético, el cual fue mezclado con una disolución acuosa del producto obtenido de la hidrólisis de la lignina y luego añadido a una disolución de vaselina para microemulsionar. Posteriormente, se agregó el glutaraldehído como agente entrecruzante. Se obtuvieron microcápsulas con tamaños entre 5 y 10 µm. Estas microcápsulas son un material promisorio ya que, mediante la formación del complejo, se puede aumentar la solubilidad del quitosano y estabilizar los polifenoles, manteniendo así sus propiedades antioxidantes. Los resultados preliminares obtenidos en esta investigación, muestran el potencial de este material para el encapsulamiento de fármacos y pesticidas.