Publications by authors named "Rubens M Filho"

This manuscript reports for the first time a heterogenous catalytic route to monoglycerides (MAGs) from microalgal oil. Microalgae is an important biomass source with high-value applications, such as food ingredients with essential fatty acids. To date, the glycerolysis of microalgae has only been investigated for a microbial oil (Schizochytrium sp.

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Lithium-oxygen batteries show promising energy storage potential with high theoretical energy density; however, further investigation of chemical reactions is required. In this study, experimental Raman and theoretical analyzes are performed for a Li-O battery with LiClO/dimethyl sulfoxide (DMSO) electrolyte and carbon cathode to understand the role of intermediate species in the reactional mechanism of the cell using a high donor number solvent. Operando Raman results reveal reversible changes in the DMSO bands, in addition to the formation and decomposition of LiO.

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Microalgae lipid accumulation can be accomplished by different strategies rather than naturally reaching the stationary phase. Many studies employ nitrogen (N) depletion to improve lipid production; however, this approach might not be a suitable alternative when growth in wastewater is attempted. Agro-industry effluents in particular can have high concentrations of N, so nutrient removal is also required.

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Lactide dimer is an important monomer produced from lactic acid dehydration, followed by the prepolymer depolymerization process, and subsequent purification. As lactic acid is a chiral molecule, lactide can exist in three isomeric forms: L-, D-, and -lactide. Due to its time-consuming synthesis and the need for strict temperature and pressure control, catalyst use, low selectivity, high energy cost, and racemization, the value of a high purity lactide has a high cost in the market; moreover, little is found in scientific articles about the monomer synthesis.

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Li-O battery technology offers large theoretical energy density, considered a promising alternative energy storage technology for a variety of applications. One of the main advances made in recent years is the use of soluble catalysts, known as redox mediators (RM), decreasing the charge overpotential and improving cyclability. Despite its potential, much is still unknown regarding its dynamic, especially over higher loading electrodes, where mass transport may be an issue and the interplay with common impurities in the electrolyte, like residual water.

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It is common to find in the literature different values for the working voltage window (WVW) range for aqueous-based supercapacitors. In many cases, even with the best intentions of the widening the operating voltage window, the measured current using the cyclic voltammetry (CV) technique includes a significant contribution from the irreversible Faradaic reactions involved in the water-splitting process, masked by fast scan rates. Sometimes even using low scan rates is hard to determine precisely the correct WVW of the aqueous-based electrochemical capacitor.

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Lactic acid is a high-value molecule with a vast number of applications. Its production in the biorefineries model is a possibility for this sector to aggregate value to its production chain. Thus, this investigation presents a biorefinery model based on the traditional sugar beet industry proposing an approach to produce lactic acid from a waste stream.

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The rates of recurrent venous thromboembolism (RVTE) vary widely, and its causes still need to be elucidated. Statistical multivariate methods can be used to determine disease predictors and improve current methods for risk calculation. The objective of this study was to apply principal component analysis to a set of data containing clinical records of patients with previous venous thromboembolism and extract the main factors that predict recurrent thrombosis.

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CoCrMo alloys have been used for several decades in implantable devices due to their favourable mechanical properties, low wear rate in addition to good biocompatibility and high corrosion resistance. These alloys are conventionally produced via casting and/or forging route, however additive manufacturing techniques being recently employed in their fabrication. In this work, CoCrMo samples were produced by direct metal laser sintering additive manufacturing process.

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Article Synopsis
  • - Syngas fermentation offers a promising method for converting waste gas into ethanol and other chemicals, working well alongside gasification to enhance waste material valorization through process optimization.
  • - The study introduces a dynamic model for syngas fermentation involving specific bacteria, which incorporates various factors such as gas-liquid interactions, biomass changes, and product yield to optimize the fermentation process.
  • - Key findings revealed that while maximizing ethanol productivity and CO conversion can conflict in CO-rich environments, increasing hydrogen content can enhance productivity without sacrificing CO conversion, achieving a maximum predicted productivity of 2 g·L·hr under specific gas compositions and conditions.
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In flexible ethanol-butanol plants, low tolerance to butanol by solventogenic clostridia (and resulting dilute fermentation) results in considerable number of empty fermentors whenever production focuses on ethanol. This research identified scenarios in which vacuum fermentation (in-situ vacuum recovery) may be applied to solve this problem. We conducted ethanol (Saccharomyces cerevisiae) and ABE (Clostridium beijerinckii NCIMB 8052) batch vacuum fermentations of eucalyptus hydrolysates according to the distribution of sugars in a flexible plant.

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This work presents the rheological assessment of poly(methyl methacrylate) (PMMA) polymers synthesized in a dedicated pilot-scale plant. This material is to be used for the construction of scaffolds via Rapid Prototyping (RP). The polymers were prepared to match the physical and biological properties required for medical applications.

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This paper presents the techno-economics of greenfield projects of an integrated first and second-generation sugarcane biorefinery in which pentose sugars obtained from sugarcane biomass are used either for biogas (consumed internally in the power boiler) or n-butanol production via the ABE batch fermentation process. The complete sugarcane biorefinery was simulated using Aspen Plus®. Although the pentoses stream available in the sugarcane biorefinery gives room for a relatively small biobutanol plant (7.

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The techno-economics of greenfield projects of a first-generation sugarcane biorefinery aimed to produce ethanol, sugar, power, and n-butanol was conducted taking into account different butanol fermentation technologies (regular microorganism and mutant strain with improved butanol yield) and market scenarios (chemicals and automotive fuel). The complete sugarcane biorefinery with the batch acetone-butanol-ethanol (ABE) fermentation process was simulated using Aspen Plus®. The biorefinery was designed to process 2 million tonne sugarcane per year and utilize 25%, 50%, and 25% of the available sugarcane juice to produce sugar, ethanol, and butanol, respectively.

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Much of the controversy surrounding second generation ethanol production arises from the assumed competition with first generation ethanol production; however, in Brazil, where bioethanol is produced from sugarcane, sugarcane bagasse and trash will be used as feedstock for second generation ethanol production. Thus, second generation ethanol production may be primarily in competition with electricity production from the lignocellulosic fraction of sugarcane. A preliminary technical and economic analysis of the integrated production of first and second generation ethanol from sugarcane in Brazil is presented and different technological scenarios are evaluated.

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Bioabsorbable polymers are considered a suitable alternative to the improvement and development of numerous applications in medicine. Poly-lactic acid (PLA,) is one of the most promising biopolymers due to the fact that the monomers may produced from non toxic renewable feedstock as well as is naturally occurring organic acid. Lactic acid can be made by fermentation of sugars obtained from renewable resources as such sugarcane.

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Simultaneous acetone butanol ethanol (ABE) fermentation by Clostridium beijerinckii P260 and in situ product recovery was investigated using a vacuum process operated in two modes: continuous and intermittent. Integrated batch fermentations and ABE recovery were conducted at 37 °C using a 14-L bioreactor (7.0 L fermentation volume) containing initial substrate (glucose) concentration of 60 g/L.

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The objective of this work was to determine the optimum conditions of sugarcane bagasse pretreatment with lime to increase the enzymatic hydrolysis of the polysaccharide component and to study the delignification kinetics. The first stage was an evaluation of the influence of temperature, reaction time, and lime concentration in the pretreatment performance measured as glucose release after hydrolysis using a 2(3) central composite design and response surface methodology. The maximum glucose yield was 228.

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Biodiesel is a clean burning fuel derived from a renewable feedstock such as vegetable oil or animal fat. It is biodegradable, non-inflammable, non-toxic, and produces lesser carbon monoxide, sulfur dioxide, and unburned hydrocarbons than petroleum-based fuel. The purpose of the present work is to present an efficient process using reactive distillation columns applied to biodiesel production.

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Distilled glycerides are obtained through distillation of the system mono-diglycerides which is produced from the esterification reaction between a triglyceride with glycerol. In this work, monoglycerides (MG) and diglycerides (DG) are produced through lipase-catalyzed glycerolysis of soybean oil using Candida antarctica B in a solvent-free system. To separate the products of the reaction in order to obtain essentially MG and an oil of DG, it is necessary to use a suitable process in order to preserve the stability of the components and to keep the products free of inappropriate solvents.

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The accurate description of the kinetics and robust modeling of biotechnological processes can only be achieved by incorporating reliable methodologies to easily update the model when there are changes in operational conditions. The purpose of this work is to provide a systematic approach with which to perform model parameters screening and updating in biotechnological processes. Batch experiments are performed to develop a mechanistic model, considering the effect of temperature on the kinetics, and further experiments (batch fermentations using sugar cane molasses from a different harvest) are used to validate the effectiveness of screening before parameters updating.

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Soybean oil deodorized distillate (SODD) is a byproduct from refining edible soybean oil; however, the deodorization process removes unsaponifiable materials, such as sterols and tocopherols. Tocopherols are highly added value materials. Molecular distillation has large potential to be used in order to concentrate tocopherols, because it uses very low levels of temperatures because of the high vacuum and short operating time for separation and, also, it does not use solvents.

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Monoglycerides (MG) are emulsifiers widely used in food and pharmaceutical industries. Current industrial processes for MG production consist of the interesterification of triglycerides with glycerol (GL), in the presence of inorganic catalysts at high temperatures (>200 degrees C). This reaction is known as glycerolysis and produces a mixture of approx 50% of MG.

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Five lipases were screened (Thermomyces lanuginosus free and immobilized forms, Candida antarctica B, Candida rugosa, Aspergillus niger, and Rhizomucor miehei) to study their ability to produce monoglycerides (MG) and diglycerides (DG) through enzymatic glycerolysis of soybean oil. Lipase from C. antarctica was further studied to verify the enzyme load (wt% of oil mass), the molar ratio glycerol/oil, and the water content (wt% of glycerol) on the glycerolysis reaction.

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