Maximization of monomeric C5 sugars from wheat bran by using mesoporous ordered silica catalysts

The hydrolysis process of a real fraction of arabinoxylans derived from wheat bran was studied. The influence of catalyst type and loading, reaction time and different metal cations were discussed in terms of the hydrolysis yield of arabinose and xylose oligomers as well as the formation of furfural as degradation product. A high yield of arabinoxylans into the corresponding monomeric sugars (96 and 94% from arabino- and xylo-oligosaccharides, respectively) was obtained at relatively high temperatures (180 °C) and short reaction times (15 min) with a catalyst loading of 4.8 g of RuCl3/Al-MCM-48 per g of initial carbon in hemicelluloses.CTQ2015-64892-R (MINECO/FEDER

Obtención de gas de síntesis a partir de biomasa utilizando catalizadores de níquel

En este proyecto se ha dimensionado una planta industrial para la producción de gas de síntesis a partir de biomasa forestal. La situación actual de agotamiento de materias primas de origen fósil, supone una oportunidad para el desarrollo de procesos de obtención de gas de síntesis a partir de materias primas renovables como es la biomasa. Se propone un proceso en dos etapas principales utilizando catalizadores de níquel en ambas. La primera de ellas consiste en la pirólisis de la biomasa inicial en un reactor a 750oC, utilizando N2 como gas inerte. El residuo carbonoso de esta primera etapa, denominado char, se lleva a un segundo proceso de gasificación, que opera con vapor de agua a 850oC, con el fin de obtener un gas de síntesis de mayor calidad, para su utilización posterior en síntesis de combustibles. El proyecto incluye también la propuesta de proceso para la preparación del catalizador.Departamento de Ingeniería Química y Tecnología del Medio AmbienteGrado en Ingeniería Químic

10th World Congress of Chemical Engineering,

Extraction and Hydrolysis of arabinoxylans have been studied using RuCl3 catalysts over different mesoporous silica supports. Acidity of the catalyst is a key parameter for these processes: the higher the Acidity, the higher the Yield. Ru+3 has demonstrated to be active, as it is a moderate Lewis acid. Arabinose is always faster released than xylose: Arabinose belongs to side chains and it is linked by beta-glycosidic bonds (weak). Xylose belongs to the backbone and it is linked by β -glycosidic bonds (strong).Proyecto CTQ2015-64892-R (MINECO/FEDER

Wheat bran biorefinery: Valorization of hemicelluloses to sugar alcohols. Fractionation - Hydrolysis - Purification - Hydrogenation

Esta tesis doctoral se encuadra dentro de los procesos de valorización de biomasa para la obtención de productos de alto valor añadido. En concreto, en esta tesis se ha desarrollado un proceso compuesto por varias etapas secuenciales para la producción de alcoholes de azúcar a partir de salvado de trigo, una biomasa agrícola. El proceso global se compone de 4 etapas principales. La primera de ellas es el fraccionamiento del salvado de trigo para solubilizar en agua su parte hemicelulósica, en concreto la fracción de arabinoxilanos. La segunda etapa consiste en la hidrólisis de estos arabinoxilanos en los correspondientes monómeros, es decir, en arabinosa y xilosa. En la tercera etapa, se han obtenido azúcares de elevada pureza mediante un proceso de purificación. Y la última etapa corresponde a la hidrogenación de estos azúcares purificados, mayoritariamente arabinosa y xilosa, para obtener los correspondientes alcoholes de azúcar, es decir, arabitol y xilitol.Departamento de Ingeniería Química y Tecnología del Medio AmbienteDoctorado en Ingeniería Química y Ambienta

Extraction of arabinoxylans from wheat bran using hydrothermal processes assisted by heterogeneous catalysts

The extraction/hydrolysis process of arabinoxylans from destarched wheat bran was studied in this work using different mesoporous silica supports and the corresponding RuCl3-based catalysts. The effects of temperature, time, catalyst supports and ruthenium catalysts were investigated and discussed in terms of the arabinoxylans extraction yield and their polymerization degree. Relatively high temperatures (180 °C), short extraction times (10 min) and RuCl3 supported on Al-MCM-48 led to a high amount of extracted arabinoxylans (78%) with a low molecular weight (9 kDa). Finally, a relation between the operating conditions, the arabinoxylans extraction yield and the molecular weight was stablished based on the obtained results.CTQ2015-64892-R (MINECO/FEDER

Heterogeneous catalysis for the extraction of arabinoxylans from wheat bran

Introduction The conversion of biomass within biorefineries into chemicals and energy is seen as a real possibility for the substitution of fossil resources. Raw materials of high lignocellulosic content are an interesting option. Besides wood and non-food crops, agricultural residues like straw and corn stover as well as other by-products of various origins are of high interest as feedstocks. Wheat bran represents such a by-product, which accrues in enormous quantities during the production of white wheat flour. It is estimated that 150 million tons are produced per year worldwide [1]. Currently wheat bran is mainly used as a low value ingredient in animal feed. Arabinoxylans are the most abundant structural polysaccharides in wheat bran, and they can be suitable compounds for the production of sugar alcohols. In general terms, the conversion of these hemicellulosic components from biomass into sugar alcohols is a two‑step reaction: 1) extraction and hydrolysis of arabinoxylans and 2) hydrogenation of these hemicelluloses into polyols (Figure 1). Please click Additional Files below to see the full abstract

From Biomass to Sugar Alcohols: Purification of Wheat Bran Hydrolysates Using Boronic Acid Carriers Followed by Hydrogenation of Sugars over Ru/H-ZSM-5

Wheat bran is a lignocellulosic waste of milling industry. It contains hemicelluloses, which can be valorized into arabitol and xylitol via a few-step approach. It begins with extraction and hydrolysis of hemicelluloses to produce a solution of xylose and arabinose, along with proteins and inorganic salts. This work focuses on the purification of sugars of this hydrolysate and the subsequent catalytic production of sugar alcohols. A purification process based on the recovery of sugars by anionic extraction with a boronic acid, followed by back-extraction and a further refining step with ion exchange resins is described. After this process, a high purity sugars solution (∼90%) free of inorganic elements and proteins was obtained. The feasibility of the process was also highlighted by a successful recycling of the organic phase containing the boronic acid. The hydrogenation of purified sugars was then performed over Ru/H-ZSM-5. A high yield into pentitols of ∼70% with 100% selectivity was achieved. Importantly, the catalytic hydrogenation of sugars in the hydrolysate prior to purification did not occur. We determined that proteins caused the deactivation of the catalyst, and consequently, the inhibition of the production of sugar alcohols.Ministerio de Economía, Industria y Competitividad - Fondo Europeo de Desarrollo Regional (project CTQ2015-64892-R

4th International Congress on Catalysis for Biorefineries (CatBior 2017)

The production of C5 sugars from wheat bran has been optimized in a two-step process consisting of a hydrothermal fractionation of AX and their subsequent hydrolysis using RuCl3/Al-MCM-48. From the fractionation step, almost 80% of the AX were solubilized into the aqueous phase. After the hydrolysis process, a high hydrolysis yield of xylo- and arabino- oligosaccharides into xylose (94%) and arabinose (96%), respectively, has been achieved. Ru+3, as a moderate Lewis acid, has demonstrated to be active in the fractionation and hydrolysis processes of the hemicellulosic part of wheat bran.Project CTQ2015-64892-R (MINECO/FEDER