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Papers by George Jackson de Moraes Rocha

Cadernos de Engenharia de Estruturas, Jan 28, 2014

Centro Azúcar, 2013

El uso de los materiales lignocelulósicos como fuentes de biocombustibles, químicos y alimentos e... more El uso de los materiales lignocelulósicos como fuentes de biocombustibles, químicos y alimentos en las biorrefinerías del futuro es un tópico de interés científico creciente. La refinación de la biomasa lignocelulósica implica una etapa de fraccionamiento que puede ser realizada por distintos métodos, incluyendo el uso de ácidos y disolventes orgánicos. El uso del glicerol en la refinación de biorrecursos lignocelulósicos permitiría aprovechar el exceso de ese producto generado en la producción de biodiesel. En el presente trabajo se investigó el uso del glicerol como agente deslignificante en el fraccionamiento de bagazo de caña de azúcar. La deslignificación se realizó con glicerol al 50 %, a 121oC durante 2 horas. En algunos experimentos la deslignificación fue catalizada con NaOH. Se investigó, además, la combinación de la prehidrólisis ácida (a 121, 160 y 195oC) con el tratamiento con glicerol. Se logró una alta remoción de la lignina y una buena preservación de la celulosa. Lo...

Chemical Engineering Transactions, 2016

A promising use of sugarcane bagasse is for cellulosic ethanol production. One step of this produ... more A promising use of sugarcane bagasse is for cellulosic ethanol production. One step of this production is the enzymatic hydrolysis process. A residual stream from this process is mainly composed of lignin and some non-hydrolysed cellulose fibers. In order to extend the application of the biorefinery concept to second generation (2G) ethanol production, the residue generated in this process could be used as raw materials for new processes to obtain value-added products. Besides, fully utilization of the residues produced in the enzymatic hydrolysis process is a feasible method to reduce cost. Lignin has a potential to replace petroleum- based materials, which are increasingly scarce and expensive, in many industrial applications, such as phenolic resins. The original source, the extraction method used and the process by which lignin was stemmed change its physicochemical characteristics. Thus, the suitability of lignin as raw materials into value- added products can vary widely. Bear...

ACS Sustainable Chemistry & Engineering, 2016

A laboratory (2 L) scale alkaline pretreatment with and without anthraquinone addition was perfor... more A laboratory (2 L) scale alkaline pretreatment with and without anthraquinone addition was performed to evaluate the influence of temperature, alkaline loading, residence time, heating and stirring system on mass yield and solubilization rates of the main components. The best conditions were scaled up to pilot scale (350 L), and enzymatic conversion of structural carbohydrates into sugars for cellulosic ethanol production was analyzed. The tested conditions were 130–170 °C, 0.5–1.5% NaOH, 30–90 min with and without 0.15% w/w of anthraquinone (AQ). The AQ addition did not lead to substantial cellulose preservation in the laboratory scale; however, in the pilot scale the AQ addition resulted in 67.4% and 28.5% of cellulose preservation for reactions at 130 °C, 1.5% NaOH, 30 min (5Pil) and 170 °C 1.5% NaOH, 30 min (7Pil) respectively in relation to those studies without addition. The most efficient heating and agitation system of pilot reactor was probably the determining factor for effective performance. Te...

Sugarcane bioethanol — R&D for Productivity and Sustainability, 2014

Fuel Processing Technology, 2012

Desalination and Water Treatment, 2011

Journal of Bioresources and Bioproducts, 2021

According to the National Company of Supplying (CONAB) in 2017 alone, the national production of ... more According to the National Company of Supplying (CONAB) in 2017 alone, the national production of acai pulp reached 219 855 t, equating to 180 million dollar (USD). Almost 85% of the weight of fruit is constituted by residual biomass, even though researches have highlighted important applications for this biomass, most of it is discarded as organic waste. Thus, it is relevant to envisage in-depth studies about how to use these residues, particularly regarding the environmental impact of its target destination. Nanocrystalline cellulose (CNC) and lignin are organic derivatives obtained through the physical-chemical treatment of lignocellulosic biomass. Both are abundant and currently considered as biopolymers because of their structural characteristics and their diverse applications in food and the medical field. This work presents the mass yields achieved and the physical-chemical characteristics of the lignocellulosic derivatives extracted from the fiber of the acai berry. A statistical design was used to define the influence of process variables as temperature, reaction time and fiber size on the yield of these byproducts. A maximum yield close to 64% of type I CNC, with 45% of crystallinity degree was achieved at the minimum condition of temperature and fiber size. Additionally, through rheological analysis, it was possible to predict the nanocrystal aspect ratios, ranging from 71 to 125. The extracted lignin was rich in methoxy groups, p-coumaryl alcohol and p-coumaric acid, and its structural unit's low state of aggregation can be an indication of low molecular weight, which envisions an appropriate use for this lignin to produce commodity chemicals.

Hydrothermal Processing in Biorefineries, 2017

The pretreatment process technologies have been developed along the years in order to provide met... more The pretreatment process technologies have been developed along the years in order to provide methods which can alter the lignocellulosic structure and release the carbohydrate content for biofuel production. These processes are based on physical, chemical, and biological methods (Galbe and Zacchi 2002; Taherzadeh and Karimi 2007; Alvira et al. 2010; Geddes et al. 2011; Ruiz et al. 2012). The main challenge of producing fuel ethanol from renewable lignocellulosic biomass is overcoming the cost-limiting factors associated with these various stages of biomass processing (Iranmahbooba et al. 2002), and for this, further advances are required, with a complete understanding of pretreatments, enzymatic hydrolysis, and ethanol production (Yang and Wyman 2008). Hydrothermal pretreatment is a potential method, since it solubilizes a large extent of hemicellulosic fraction and releases lignin fragments with low molecular weight in the liquor, reducing the recalcitrance (Petersen et al. 2009). This process operates with pressurized hot water in temperatures that usually range from 150 to 230 C and reaction times from seconds to hours (according to the reaction temperature) (Gurgel et al. 2014). Since lignocellulosic materials undergo hydrolysis reactions in the presence of the hydronium ions generated by water autoionization, which act as catalysts, this method has been gaining increasing attention as environmentally friendly solvent (Zhuang et al. 2015). During the pretreatment, acetic acid and other organic acids are liberated as a result of the cleavage of O-acetyl and uronic acid substitutions on hemicelluloses

Bioethanol, 2016

The economics for production of secondgeneration (2G) ethanol from sugarcane bagasse in large sca... more The economics for production of secondgeneration (2G) ethanol from sugarcane bagasse in large scale, competing with the cogeneration of electric energy, is still not consolidated. In this scenario, the key for feasibility may be the biorefinery concept, a multiproduct industry using biomass fractions to produce energy, chemicals and by-products. Xylooligosaccharides (XOS) are oligomers of xylose often used as additives in food, animal feeds, and drugs. The effect of NaOH pretreatment on the recovery of xylan for XOS production from sugarcane bagasse under different conditions, namely 121°C, 4-7% NaOH loading, was investigated. The best condition was 4% NaOH and 60 min of reaction, achieving 55% of xylan extraction, without monomer production. In order to produce XOS, soluble and immobilized xylanases were used to hydrolyze commercial birchwood xylan (as control) and the sugarcane bagasse xylan. The immobilized endoxylanase produced XOS with 37% of xylobiose and 20% of xylotriose (w/...