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Producción Científica, Different lignins from different sources (hardwoods, softwoods and crop residues) and obtained as by-products of different processes such pulping or biorefining were depolymerized in alkaline supercritical water (SCW: 386 °C and 260 bar) in an intensified continuous process to produce high value-added compounds with low-molecular-weight in only 300 ms of reaction time. The products obtained were analysed to determine the yield, selectivity to monomers, chemical structure and molecular weight distribution. The char formation was low in most cases, but the proportion of heavy and light oils were variable upon the starting material used. The monoaromatics yield depends mostly on the type of lignin utilized being the non-wood biorefinery lignins less suitable for monomers production than the technical wood ones (13-8%). The monomer distribution depends on the biomass of origin and the pulping method. This technology is equally effective when directly treating a black liquor and better results are obtained if compared to the corresponding isolated lignin., Ministerio de Ciencia, Innovación y Universidades - Fondo Europeo de Desarrollo Regional (grants CTQ2016-79777-R and PID2019-105975 GB-I00), Junta de Castilla y Leon - Fondo Europeo de Desarrollo Regional (grants VA277P18 and CLU-2019-04)

Epigenetic mechanisms are thought to be involved in the reduced developmental capacity of early prepubertal ewe oocytes compared to their adult counterparts. In this study, we have analyzed the global DNA methylation pattern and in vitro meiotic and developmental competence of oocytes at the germinal vesicle (GV) stage obtained from adult and 3-month-old donors. All oocytes were aspirated from antral follicles with a diameter ≥3 mm, and DNA methylation on 5-methylcytosine was detected by immunofluorescence using an anti-methyl cytosine antibody. The main global chromatin configuration pattern shown by both prepubertal and adult ovine oocytes corresponded to condensed chromatin localized close to the nuclear envelope (the SNE pattern). Immunofluorescence showed that a global bright nuclear staining of 5-methylcytosine (5-mC) occurred in all germinal vesicle stage oocytes and matched the propidium iodide staining pattern. The total fluorescence intensity values of lamb GVs were not lower than those observed in adult GVs. The meiotic competence and cleavage rates were similar in adult and prepubertal oocytes, however, the developmental competence of embryos to reach blastocysts was higher for adult oocytes than lamb oocytes (p

Producción Científica, This article seeks to be a handy document for the academy and the industry to get quickly up to speed on the current status and prospects of biomass pretreatment for biorefineries. It is divided into two biomass sources: vegetal and animal. Vegetal biomass is the material produced by plants on land or in water (algae), consuming sunlight, CO2, water, and soil nutrients. This includes residues or main products from, for example, intensive grass crops, forestry, and industrial and agricultural activities. Animal biomass is the residual biomass generated from the production of food from animals (e.g., manure and whey). This review does not mean to include every technology in the area, but it does evaluate physical pretreatments, microwave-assisted extraction, and water treatments for vegetal biomass. A general review is given for animal biomass based in physical, chemical, and biological pretreatments.

Caffeine and carvacrol were encapsulated using supercritical CO2 (sc-CO2) impregnation in MOFs, MIL-53(Al) and Mg-MOF-74, at different contact times. High additive loadings were achieved, 32.1 and 34.3% for caffeine, and for carvacrol 34.4 and 30.1%, respectively. The sc-CO2 encapsulation was more effective compared to the typical liquid phase encapsulation in ethanol. In fact, the encapsulation in Mg-MOF-74 was only possible in sc-CO2, null loading was observed in the liquid ethanol phase process. The products required no purification and the excess of additives could be reused. In all the studied cases, the materials maintained their crystalline structure and MIL-53(Al) displayed its characteristic flexibility adapting its structure to the additives. The total release of caffeine and carvacrol from Mg-MOF-74 was produced after 5 h in distilled water, while in the case of MIL-53(Al) no release was observed for 10 days., The authors acknowledge financial support from the Aragón Government (DGA, T43-17R) and the European Social Fund. Íñigo Echániz is acknowledged for his help with Raman spectrometer use. Soraya Rodríguez Rojo acknowledges Junta de Castilla y León and FEDER 2014-2020 for her postdoctoral contract under Project VA040U16.

Wine lees are rich in anthocyanins (AC), natural colorants with health promoting properties. The extraction kinetics of AC from different wine lees in conventional solid-liquid extraction were studied for the first time. The influence of parameters such as temperature, solid-liquid ratio (RS-L) and type of solvent (hydro-alcoholic mixtures) was also studied. Furthermore, microwaves (MW) and ultrasounds (US) were used as pre-treatments (a prior step to the conventional extraction) in order to increase AC yield. Maximum extraction yield (2.78 mgMALVIDIN-EQUIVALENTS/gDRY-LEES) was achieved after 15 minutes at 25ºC, with a RS-L of 1/10 (g/mL) and with a 50%vol. ethanol mixture. When MW were used AC extraction yield was doubled (6.20 mgMALVIDIN-EQUIVALENTS/gDRY-LEES) and the required time to achieve a constant yield was reduced (from 15 min to 90s). Meanwhile, US only shortened extraction time in less proportion (from 15 to 5 min). Putative identification of main extract compounds was performed by LC/MS-MS., 2019-09-01

This study re-analyzes literature data on S. platensis’ chlorophyll (CHL) extraction using 5-25 cm3 of 20–80% v/v ethanol in water (static modifier) and 82.5–62.5 cm3 of CO2 at 50 °C and 40 MPa. Under these conditions, a CO2-expanded aqueous ethanol (liquid) phase coexists with an aqueous-ethanol-modified CO2 (SCF) phase in the extraction vessel. Authors hypothesize the resulting extraction is a two-step process consisting of slow transfer of CHL from the substrate to the liquid phase, followed by fast (equilibrium) transfer of CHL to the SCF phase. For analysis, we described the ternary (CO2 + ethanol + water) system at 50 °C and 40 MPa using Peng-Robinson Equation of State and Wong-Sandler mixing rules with binary interaction parameters describing phase equilibrium of binaries (CO2 + ethanol), (ethanol + water), and (CO2 + water). Authors propose a simple mathematical model of the extraction process, and identify research needs to validate/refine it.

The sugarcane sector in Brazil has undergone a major modernization in the last thirty years. Embracing the biorefinery concept, this sector is investigating bioproduct diversification and mostly putting a lot of effort and investment on second generation ethanol production. In this context, the investigation of the integration of a third generation biofuel production using microalgae to the sugarcane biorefinery seems an important starting point. This study evaluates the integration of microalgae growth and processing to a sugarcane biorefinery producing first and second generation ethanol using process simulation tools. Microalgae are cultivated using CO2 produced during fermentation of ethanol and it is processed using supercritical fluid extraction technology in order to obtain lipids rich in high added-value compounds, carotenoids. The results showed that the integration of microalgae biomass processing without previously drying with the sugarcane biorefinery is not attractive from the thermo-economic point. When considering the extraction of dried microalgae the extraction process could be thermal integrated to the sugarcane biorefinery producing ethanol without the need of buying external fuel. The amount of CO2 used as solvent to the supercritical fluid extraction was the main factor that influenced the economic viability of the process. When microalgae pretreatment by cell disruption or co-solvent extraction was considered, it was possible to decrease the amount of CO2 used in the process and an increase in process yields was consequently achieved. The use of a co-solvent in the extraction increased in 1.4 and 2.4 times lipids and carotenoids extraction, respectively, and presented a lower investment when comparing with microalgae extraction without cell disruption.

Producción Científica, Sugar beet pulp (SBP) is the major by-product in sugar industry. To make profit out of this undervalued residue, the FASTSUGARS process was proposed as a solution, combining the advantages of supercritical water as hydrolysis medium with very short reaction times in the so-called ultrafast reactors. Operating at 390 °C, 25 MPa and reaction times between 0.11 and 1.15 s it was possible to convert SBP into sugars and to obtain a lignin-like solid fraction. The highest yields of C-6 and C-5 sugars (61 and 71% w/w, respectively) were obtained at 0.11 s with the lowest yield of degradation products. The solid product obtained at 0.14 s was thoroughly analyzed by acid hydrolysis, TGA and FTIR analysis to prove its enhanced thermal properties and aromaticity. The FASTSUGARS process demonstrated being a versatile and promising technology to be integrated in the future biorefineries., Ministerio de Economía, Industria y Competitividad (Project CTQ2013-44143-R and CTQ2016-79777-R)

Producción Científica, Kraft lignin was rapidly depolymerised in a continuous reactor using sub- and supercritical water. The reaction yielded an aromatic oil rich in high value aromatic monomers such as guaiacol, vanillin, acetovanillone and homovanillic acid. Different temperatures between 300 and 400 °C and reaction times from 60 ms were studied. An increment in reaction time at every temperature studied promoted secondary reactions of repolymerisation of the lignin products. Those undesired reactions were more relevant as temperature increased. An optimal temperature of 386 °C at a reaction time of 170 ms was found, with a maximum yield in phenolic compounds obtained. At those conditions, a bio-oil containing low molecular weight compounds was obtained with a yield of 44.6 %. A selectivity to the four cited monomers of 9.9 % was achieved, with little formation of solid residue (3.5 %). A simple kinetic model was proposed to describe the yield for the different fractions and fitted to experimental data., Ministerio de Economía y Competitividad y Comisión Europea (FEDER) Proyecto (CTQ201679777-R), Ministerio de Educación (beca predoctoral FPU15 / 00409)

Producción Científica, Arbutus unedo L., commonly known as the strawberry-tree fruit, is an endemic species of the Mediterranean flora. Microwave extraction technology has been considered as a fast and “green” method for the production of extracts rich in bioactive compounds, although the energy consumption is high. To overcome this bottleneck, microwave was used as a pretreatment procedure in short time periods. This technique promotes the burst of intracellular vacuoles leading to an increase in the lixiviation of phenolic compounds. Different approaches were tested, namely a solvent-free irradiation (SFI), a solvent-assisted irradiation (SAI) and a pressurized solvent-assisted irradiation (PSAI). After irradiation, a solid–liquid extraction procedure was performed using a mixture of water and ethanol. A kinetic evaluation of the total phenolic content (TPC) was performed using the Folin–Ciocalteu method. For the total anthocyanin content, a UV-spectrophotometric method was used. HPLC-UV and LC-MS were used for TPC and identification of present compounds. Microwave irradiation led to an increase in TPC of extracts after SAI (52%) and PSAI (66%) along with a reduction in time of extraction from 30 min to less than 2 min. The anthocyanin content also increased by 66% for the SAI and PSAI extractions., Fundação para Ciência e Tecnologia (fellowship SFRH/BD/52532/2014), Fundação para a Ciência e Tecnologia/Ministério da Educação e Ciência - Fondo Europeo de Desarrollo Regional (partnership PT2020), Portuguese National Mass Spectrometry Network (contracts RNEM—REDE/1518/REM/2005, ROTEIRO/0028/2013 and LISBOA-01-0145-FEDER-022125), Marie Curie Industry - Academia Partnerships and Pathways (project FP7-PEOPLE-2013-IAPP-612208)

This paper discusses the influence of reactor design and initial consistency when partially hydrolyzing microcrystalline cellulose (MCC) in supercritical water. Experiments conducted on two pilot reactors located in Finland and in Spain showed that stopping the reaction using depressurization instead of quenching, combined with a sufficiently high MCC consistency, led to significant change in reaction kinetics. A complete particle size reduction was achieved after 50 ms only due to additional shear induced degradation, with a low-molecular-weight product yield above 50 wt % and an average DP of 25. In addition, gradually increasing the MCC consistency triggered precipitation under higher apparent temperature, which affected both the morphology and structure of the product. A range of particles from ribbon-like cellulose II to shish-kebab structures to lamellar cellulose IVII crystals was obtained. Furthermore, heat requirements as low as 66 kJ.g(-1) of product confirm the high potential and versatility of this process for refining MCC into colloidal low-molecular-weight cellulose with different particle shapes and structural properties.

This study presents a thermoeconomic and environmental assessment of the extraction of lipids and proteins from wet microalgal biomass in a 3G biorefinery by two different technologies: supercritical fluid extraction (SFE) and low-pressure solvent extraction (LPSE). Simulation tools were used to study a sugarcane biorefinery producing ethanol from sugarcane juice (1G) and bagasse (2G); the microalgal growth in an open pond; and the processing of microalgal biomass into lipids, proteins and synthetic natural gas (SNG). Supercritical water gasification (SCWG) of microalgal biomass enables an increase in biofuel production of 10.2% MJ when no extraction process is considered and of 1.9% MJ when LPSE is considered. The heat demand of the proposed biorefinery with LPSE was increased by 87.8% compared with the demand of the sugarcane biorefinery without microalgal growth and processing. When the SFE process is considered, the heat demand of the overall process increased 3.2 times. SFE for wet microalgae processing is not economically attractive, as it increases the total investment by 71%. The CO2 flow used in the SFE process demonstrated to be a key factor in the thermoeconomic viability of the process. Regarding the wet processing of microalgae prior to SCWG, the best alternative studied was the use of LPSE technology.

New experiments of cellulose acetylation were performed using the ionic liquid 1-allyl-3-methylimidazolium chloride ([Amim]Cl) as a solvent, at temperatures of 80, 60 and 40 °C. An attempt is done to improve the performance of the reaction by pressurizing the reaction with 80 bar of CO2. The results indicate that scCO2 speeds up the kinetics of the reaction probably due to a reduction of the viscosity of the ionic liquid, which favours diffusion of the reactants. Additionally, CHN elemental analysis revealed that cellulose acetate (CA) obtained with scCO2 is of higher quality since it does not incorporate residues of the solvent. A kinetic model able to describe the reaction is proposed and kinetics parameters are adjusted. The model can fit experimental data from the literature obtained at different operation conditions, obtaining different kinetic constants.

Maltodextrin (MD), whey protein isolate (WPI) and pea protein isolate (PPI) have been used in this work as carrier agents in the spray drying of grape marc extract, and the obtained microparticles have been characterized in terms of drying yield, morphology (SEM), size distribution, chemical structure (FTIR), chemical composition (total phenolic and anthocyanin content), and antioxidant activity (ORAC). WPI was found to be the most effective carrier for optimizing drying yield, requiring less than 0.5:1 carrier:extract solids ratio to achieve the usual 50% yield benchmark. In vitro gastrointestinal release of total phenolics and anthocyanins indicated Fickian diffusion, with the Higuchi and Korsmeyer–Peppas models providing the best fit for the data. An accelerated stability test carried out at 40 and 60 °C revealed first-order kinetics for anthocyanin degradation. WPI formulated microparticles showed severe degradation at 40 and especially 60 °C (complete degradation after 4 days), followed by MD and PPI microparticles. Similarly, a long term stability test carried out at room temperature (25 °C) over six months showed that total phenolic content did not diminish for any of the carriers, but anthocyanin content suffered a 20% loss after 6 months for PPI and MD formulated samples, and a 50–65% loss for WPI formulated samples.

A combined process of supercritical water oxidation (SCWO) and supercritical water hydrothermal synthesis (SCWHS) in a continuous counter current reactor is reported. Acrylic acid was used as a model unsaturated carboxylic acid compound and the effects of the reaction temperature, residence time, oxidant ratio and acrylic acid concentration on chemical oxygen demand (COD) were all investigated. Two different experimental configurations for oxidant delivery were carried out in ‘pre-heated’ and ‘non-preheated’ oxidant configurations. With a stoichiometric excess of 100% oxygen, COD reduction levels of 80% (non-preheated) and 15% (preheated) were achieved with very short residence times. SCWHS was achieved through the addition of small amounts of various soluble metal salts in the cold upflow resulted in nanoparticles forming which increased the reaction rate and hydrothermal oxidation efficiency. The addition of small amounts of chromium nitrate (>5mM) results in nearly 100% COD reduction at 380 °C and residence times of 0.75 s. The potential economic benefits of combining the two processes together, in the different configurations, were also evaluated.

An ethanolic anthocyanin-rich extract was obtained from blackberry residues through ultrasound assisted extraction, and extracts were co-precipitated with the biodegradable polymer polyvinylpyrrolidone (PVP) through the supercritical antisolvent process (SAS), using carbon dioxide as antisolvent. The influence of temperature (30–45 °C), PVP concentration in the extract (0.5–4.0%) and solution flow rate (1–10 mL/min) on the SAS process were investigated. The decrease of these three parameters contributed to produce particles with smaller diameter, residual ethanol, humidity and water activity, although with higher hygroscopicity. Moreover, the increase of these parameters intensified the agglomeration of the particles. SEM images revealed co-precipitates with irregular shapes obtained at high temperatures, flow rates and PVP concentrations. FTIR analysis showed that neither extract nor PVP properties were modified in the SAS process. Good precipitation yields were achieved, indicating that the SAS process is effective and selective in the co-precipitation of anthocyanins.

Thermodynamic modeling in CFD is basically limited to the models available in the simulators. The method presented in this paper connects CFD simulators with Aspen Plus which instantaneously calculates and returns the value of any physical property required. Therefore, all the thermodynamic models and compounds available in Aspen Plus can be implemented in CFD simulations. The connection, created via Matlab and Excel-VBA, has been validated solving two identical CFD simulations first selecting a thermodynamic model available in the simulator and then connecting the simulator with Aspen Plus and selecting the same model. The maximum absolute average deviation between the density and viscosity values obtained in both simulations, for the two case studies analyzed, is lower than 0.7% which demonstrates the proper interconnection. The accuracy of the results obtained modeling multicomponent mixtures and supercritical fluids prove the applicability of the method to any scenarios.

Catalyst design and surface chemistry have long been regarded as the major foundations for the catalytic activity of carbon-based catalysts. However, surface modification of carbon-based catalysts typically involves huge quantities of strong acids that eventually leach into the solution contaminating the target compounds. We have previously demonstrated that the mixture of reduced graphene oxide (rGO) and residual cellulose would generate additional glucose after the first cycle by simply elevating the temperature. In this study, we sought to understand how rGO under microwave (MW)-subcritical water (subH2O) facilitates the depolymerization of cellulose. It was found out that the MW sensitizing properties of rGO improved, enhancing the electronic transport properties. The partial removal of functional groups has resulted into much smaller particles and formation of nanopores and nanovoids which facilitated the precise cleaving of the glycosidic bonds with glucose yields reaching up to 66 ± 4 wt% in as short as 5 min. The yield highly correlates with the H3O+/OH− concentration and hugely depends on the rGO structure that varies according to the synthesis method, preferably in the absence of water. The depolymerization mechanism takes place via random scission. This study indicates that rGO, in spite of having fewer functionalities than pristine graphene oxide (GO), can still be used for catalysis even without surface modification in combination with MW and subH2O.

The objective of this study was to elucidate the effect of adding acid and alkali to hydrothermal liquefaction (HTL) of two waste biomass feedstocks: manure digestate and carbohydrate-rich food waste. HTL reactions were conducted at 300 °C for 60 min, with and without the addition of acid or base. We measured the quantity and characterized the quality of the three main HTL products: oil, aqueous and hydro-char. For both feedstocks, carbon recovery distributions had wide ranges among (1) biocrude oil (26–61 wt %), (2) aqueous product (9–49 wt %) and (3) hydro-char (1–36 wt %). The addition of acid affected HTL reactions for manure more than for food waste. For the aqueous phase, the addition of acid decreased the recovery of C1–4 carboxylic acids and increased the production of cyclic furan compounds. GC–MS analysis of the biocrude oil suggested that dehydration reactions were enhanced by adding acid to the HTL media. FTIR spectroscopy coupled with principal component analysis showed that hydro-char sample...

In this study, we discuss the difference regarding thermo-economic and environmental (water intake) aspects between two methods of biomass hydrolysis. A thermo-economic model was developed using Aspen Plus® and MATLAB software in order to analyze the energy efficiency, as well as, the economic impact of the hydrolysis process integrated into a traditional ethanol production process from sugarcane. The study aimed at comparing the enzymatic route for sugarcane bagasse ethanol production with the supercritical water-based one. The use of supercritical water hydrolysis (SCWH) process showed promising results, being the process energetically self-sufficient when considering pumping of liquid streams with biomass content of 20% and the decompression of the steam separated after SCWH with a turbine, in order to produce electricity. In terms of economics, the biorefinery concept using enzymatic route presented the highest production costs due to the higher total investment cost and the cost for the raw materials, which is 14% higher than the biorefinery with SCWH, giving a payback time for the investments of 7.5 years, meanwhile 6.2 for the SCWH route. Also better results were obtained for water intake for the SCWH option, being lower than the maximum permitted for a new investment on the Brazilian sugarcane sector.

Polysaccharide aerogels are a good alternative as carriers for drug delivery, since they allow high loading of the active compounds in matrices that are non-toxic, biocompatible and from a renewable feedstock. In this work, barley and yeast β-glucans aerogels were produced by gelation in aqueous solution, followed by solvent exchange and drying with supercritical CO2. First, viscoelastic properties and melting profile of the hydrogels were determined. Then, the obtained aerogels were analyzed regarding morphology, mechanical properties and behavior in physiological fluid. Both in the hydrogels and in the aerogels, big differences were observed between barley and yeast β-glucans due to their different chain structure and gelation behavior. Finally, impregnation of acetylsalicylic acid was performed at the same time as the drying of the alcogels with supercritical CO2. The release profile of the drug in PBS was analyzed in order to determine the mechanism governing the release from the β-glucan matrix., Authors acknowledge Ministerio de Economía y Competitividad (MINECO) through project CTQ2013-44143-R and project PIP 063/ 147181 from Fundación General of the University of Valladolid for fi- nancial support. M. Salgado thanks to Ministerio de Educación, Ciencia y Deporte (MECD) for her FPU and mobility grants. S. Rodríguez-Rojo acknowledges to MINECO and UVa for her Juan de la Cierva fellowship (JCI-2012-14992). The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement number REGPOT-CT2012- 316331-POLARIS and from the project “Novel smart and biomimetic materials for innovative regenerative medicine approaches” RL1 − ABMR − NORTE-01-0124-FEDER-000016) co-financed by North Portugal Regional Operational Programme (ON.2–O Novo Norte), under the National Strategic Reference Framework (NSRF), through the European Regional Development Fund (ERDF)., info:eu-repo/semantics/publishedVersion

It is believed that climate change will greatly impact the relative importance of pests. The bird cherry-oat aphid, Rhopalosiphum padi L. is probably the major pest of temperate cereal crops on a world scale, it attacks all the major cereals and pasture grasses. The organic sector is in need of alternative aphicides or products that can repel this pest. In spite of the properties of plant volatiles that allow them to act as insect repellents, there is a lack of such products on the market for the agricultural sector. In this work, we tested a group of essential oils and pure compounds in a laboratory choice bioassay with R. padi (20 replications per product) and the repellency index (R.I.) was computed after 24 h. At 0.15 μl/cm2, aniseed, peppermint and lemongrass essential oils were repellent for apterous females. trans-Anethole and caryophyllene exhibited volatile toxicity to the insects (LD50 = 0.11 μl/cm2). R.I. values ranging from 68.8 to 100 were obtained using farnesol, geraniol, cis-jasmone, citral, linalool, estragole, pulegone and caryophyllene. Water emulsions of the active products were obtained (nanoemulsions with oil droplets less than 100 nm via ultrasounds for 10 min) and applied at increasing volumes using a computer-controlled spraying apparatus for the bioassay, and a dose response was obtained. Some products were active: carvone increased mobility, whilst cis-jasmone repelled R. padi at a very low dose (0.02 μl/cm2 of the treated leaf). Zetasizer measurements indicated that the smaller the particle size within the nanoemulsion, the higher the activity. Using lecithin (1:2) or lecithin plus glycerol (1:2:1) in addition to a bioactive produced larger negative Z-potential values and therefore more stable formulations without any evident effect on activity.

Producción Científica, In this work, the ionic liquid [Aliquat][Cl] was supported into alginate and silica aerogel matrices and applied as a catalyst in the cycloaddition reaction between CO2 and a bio-based epoxide (limonene oxide). The efficiency of the alginate aerogel system is much higher than that of the silica one. The method of wet impregnation was used for the impregnation of the aerogel with [Aliquat][Cl] and a zinc complex. The procedure originated a well-defined thin solvent film on the surface of support materials. Final materials were characterised by Fourier Transform Infrared Spectroscopy, N2 Adsorption–Desorption Analysis, X-ray diffraction, atomic absorption and Field Emission Scanning Microscopy. Several catalytic tests were performed in a high-pressure apparatus at 353.2 K and 4 MPa of CO2.

Producción Científica, The potential of saffron flowers as a source of polyphenols, and in particular anthocyanins, for the extraction of bioactive compounds and the production of a cyanic colorant was analyzed. A microwave pretreatment, prior to the conventional solid–liquid extraction process, was proposed as a feasible intensification step. The effectiveness of microwave pretreatment was assessed in terms of increased yield and improved quality of the final product. The operational variables studied were the pretreatment temperature (60–120 °C) and the solid–liquid ratio (0.30–0.50 g/mL). It was found that the addition of the microwave pretreatment to the conventional process allowed one to reduce extraction time by up to 12 times and to greatly improve the characteristics of the final product, using microwave energy densities as low as 0.16–0.54 kJ/mL. The extract quality was evaluated in terms of polyphenol richness (25% increase), product composition (80% of the anthocyanins was delphinidin), antioxidant capacity (boosted by the pretreatment) and color (variations in red and blue hue depending on conditions). To conclude, a microwave pretreatment in which the material is heated to a temperature of 65 °C with a solvent ratio of 0.30 g/mL was selected as the optimum to maximize process efficiency and product quality., Junta de Castilla y León - (Project VA040U16)

Holm oak (Quercus ilex) sapwood was submitted to a hydrothermal treatment and liquid fractions rich in hemicelluloses were obtained. The chemical composition as well as the molar mass were analysed during the experiments. The effect of temperature (130–170 °C) and reaction time (5–220 min) on the conversion and molar mass of the obtained hemicelluloses was investigated. The results were compared to previously published data obtained using Norway spruce. The results show that the extraction rate depends strongly on the wood species used. The maximum yield (approximately 60%) was obtained at 170 °C after 20 min. The molar mass of the hemicelluloses decreased during the extraction due to hydrolysis and the pH of the solution decreased as deacetylation occurred simultaneously. Temperature influenced significantly the hydrolysis rate of the macromolecules. Compared to Norway spruce (softwood), the average molar mass in Holm oak (hardwood) was lower under the same reaction conditions., Ministerio de Economía, Industria y Competitividad (Project CTQ2015-64892-R), Junta de Castillay León (Proyecto VA254B11-2), Ministerio de Economía, Industria y Competitividad (Project CTQ2013-44143-R), Ministerio de Economía, Industria y Competitividad (Project CTQ2011-23293), Ministerio de Economía, Industria y Competitividad (Project CTQ2011-27347)

Supercritical fluid extraction of emulsions (SFEE) is a method used for producing aqueous suspensions, containing encapsulated particles in nanometric scale, through the extraction of an organic phase from an emulsion with supercritical CO 2 . Optimization of SFEE process conditions is complex as they influence several process steps. In this work, ethyl acetate and dichloromethane o/w emulsions were prepared using soybean lecithin and polaxamers as surfactants and contacted with supercritical CO 2 . Mass transport properties were measured by magnetic suspension balances, which provide an on-line contactless weight measurement method, and a mass transfer model based on the experimental results was developed. Experimental results indicate that the density of supercritical CO 2 has a strong influence in mass transfer parameters, while no influence of other conditions such as type or concentration of surfactant was observed. In the case of dichloromethane/water emulsions, emulsion destabilization took place immediately after pressurization of the system.

Producción Científica, Barley and yeast β-glucans were selected, together with lecithin, to encapsulate resveratrol by emulsification-evaporation method to develop new and safer antifungal formulations. Different emulsification techniques were used: high-shear, high pressure and high pressure and temperature emulsification. Morphology, crystallinity, encapsulation efficiency and in vitro antifungal activity against Botrytis cinerea of the different formulations were evaluated. No significant differences between each emulsification procedure in particle size (below 90 nm) and in encapsulation efficiency (70–100%) were observed; only barley β-glucan emulsions showed lower efficiency due to the formation of a gel that retained most of the active compound. A great influence of the emulsification method and the encapsulating material on the crystallinity of the particles was observed. The highest antifungal activity (up to 53% growth inhibition) was obtained by the formulations with yeast β-glucans, indicating an enhanced absorption of encapsulated resveratrol through the cell wall of the fungus at the presence of (1–3, 1–6)-β-glucans., Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA040U16)

Porous polymeric materials are studied in tissue engineering, because they can act as support for cell proliferation and as drug delivery vehicles for regeneration of tissues. Hydrogel foaming with supercritical CO2 is a suitable alternative for the creation of these structures, since it avoids the use of organic solvents and high temperature in the processing. In this work, β-glucans were used as raw materials to create hydrogels due to their easily gelation and biological properties. The enhancement of porosity was generated by a fast decompression after keeping the hydrogels in contact with CO2. The effect of the processing conditions and type of β-glucan in the final properties was assessed regarding morphological and mechanical properties. Finally, the ability of these materials to sustainably deliver dexamethasone was evaluated. The scaffolds had good morphology and provided a controlled release, thus being suitable to be used as scaffolds and drug delivery vehicles., Authors acknowledge Ministerio de Economía y Competitividad (MINECO) through project CTQ2013-44143-R and project PIP 063/ 147181 from Fundación General of the University of Valladolid for financial support. M. Salgado thanks to Ministerio de Educación, Ciencia y Deporte (MECD) for her FPU and mobility grants. S. Rodríguez-Rojo acknowledges to MINECO and UVa for her Juan de la Cierva fellowship (JCI-2012-14992). The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement number REGPOT-CT2012-316331-POLARIS and from the project “Novel smart and biomimetic materials for innovative regenerative medicine approaches” RL1 − ABMR − NORTE-01-0124-FEDER-000016) co- financed by North Portugal Regional Operational Programme (ON.2–O Novo Norte), under the National Strategic Reference Framework (NSRF), through the European Regional Development Fund (ERDF)., info:eu-repo/semantics/publishedVersion

The present work focuses on the study of fluidization of nanoparticle agglomerates with SC-CO2 at different temperatures (308–320 K) and pressures (7.7–14.4 MPa). These conditions allow this work to be carried out in a wide range of densities, varying from 200 to 800 kg/m3. Three materials with different bulk densities were tested: aluminum oxide (Al2O3, 40 kg/m3), titanium oxide (TiO2, 90 kg/m3) and magnetite (Fe3O4, 840 kg/m3). With regards to fluidization, two different behavior patterns were detected, according to the variation of the minimum fluidization velocity (umf) in accordance with carbon dioxide density. At high densities (> 500 kg/m3) only fluid-particle interactions controlled the process, therefore, the same behavior of umf vs density was found for the three materials. Meanwhile at low densities (

Quercetin is an antioxidant compound with highly promising pharmacological properties against a wide variety of diseases. A major limitation for the clinical application of quercetin is its low bioavailability, due to its low solubility in water. In this work, quercetin is microencapsulated in a surfactant material with the objective of increasing its bioavailability. For this, quercetin is first treated using Supercritical Fluid Extraction of Emulsions in order to precipitate it in nanometric scale in an aqueous suspension, and then this suspension is further treated by Particles from Gas Saturated Solutions (PGSS)-drying technology, to obtain quercetin loaded dried particles in micrometric scale. Soy-bean lecithin and Pluronic L64® are used as surfactant and encapsulating materials. Mircoencapsulation of quercetin by lyophilisation of SFEE-produced aqueous suspensions is also studied in order to compare it with the results of PGSS-drying. Samples are characterized considering encapsulation efficiency, antioxidant activity and Franz-cell measurements of transdermal diffusion of encapsulated quercetin product as assessment of its bioavailability. It is observed that samples encapsulated by SFEE and PGSS-drying are more homogeneous and less crystalline than samples obtained by lyophilisation, which results in a higher transdermal diffusivity.

Pyrolysis is a well-known process for biomass upgrading, and a great deal of works are available about it. However, they focus on conventional lignocellulosic samples, and the information about any other less common samples, while still valuable, is very difficult to find. For instance, Brazilian ginseng (Pfaffia glomerata) is a feedstock without hemicellulose and a profitable source of target compounds (like beta-ecdysone) via an extraction process, also generating an exhausted solid. However, there is not much information about this biomass in the literature. For this reason, this work deals for the first time with the effect of different pretreatments on the thermal degradation behavior of Brazilian ginseng. To do so, thermogravimetric analysis (TGA) of the raw material and post-treated samples was done in a synthetic air atmosphere (20% oxygen). The thermograms were fitted via an autocatalytic model (deviation of 4.22%), and the calculated kinetics were used to analyze how the pretreatment modifies th...

Quercetin is an antioxidant compound with promising activity against a wide variety of diseases. However, a major limitation for the clinical application of quercetin is its low bioavailability, due to its low solubility in water. One way to increase the bioavailability of quercetin is to precipitate it in sub-micrometricscale, encapsulated by a surfactant material, using the Supercritical Fluid Extraction of Emulsions (SFEE) method. The objective of this work is to study the scale-up of a semi-continuous SFEE process for the production of microencapsulated quercetin. An experimental study of the encapsulation of quercetin in soy-bean lecithin–Pluronic L64®surfactants was performed in order to evaluate the variation of product characteristics with significant parameters, such as duration of SFEE, density of CO2 medium, used CO2/L of emulsion (kg/L), and thus determine the suitable conditions for scale-up. In addition, a themo-economic evaluation was done in order to identify bottlenecks during scale-up and promote solutions. According to the thermo-economic evaluation, the decrease of CO2 flow demonstrated to be the main parameter to decrease the energy demand and cost of manufacturing of the SFEE process. Thus further experimental studies should be done towards optimization of this parameter.

Producción Científica, Nowadays, the valorization of lignin, the major natural source of aromatics in earth, is being a challenge for the scientific community. In this study, kraft lignin is effectively converted into aromatic monomers by ultrafast depolymerization in hot and pressurized water. At reaction times below 500 ms, it is possible to avoid char formation originated from undesirable condensation reactions by controlling accurately the reaction time. Under alkaline medium, the reaction reaches an optimum point at 386ºC and 300 ms with a light oil yield of 60% with a concentration in key compounds such as guaiacol, creosol, vanillin and acetovanillone of around 20 %w/w. The char formation in this point was surprisingly low (4 %w/w). Analysis and quantification of the products allows to identify the evolution of the different reaction steps and propose plausible mechanism for the depolymerization and repolymerization stages. Furthermore, it is proven that the proposed technology is equally effective to treat directly industrial black liquors with a yield higher than 50% to light oil, containing as main monomers guaiacol (2.7%), syringol (3.0%) and syringaldehyde (7.3%)., 2020-02-15, Ministerio de Economía, Industria y Competitividad (Project CTQ2016-79777-R), Ministerio de Educación, Cultura y Deporte (Proyect FPU15/00409)

Producción Científica, Açaí (Euterpe Oleracea mart.) is a berry found in Amazon Rainforest, with a high content of polyphenols and flavonoids. This work studied the formulation of bioactive compounds extracted from E. Oleracea fruit, by impregnation in silica-aerogel. Three fruit fractions were studied: pulp, seeds and slurry, and two extracts were obtained from each fraction: an oil fraction obtained by Soxhlet extraction, and a polyphenolic-rich extract obtained by Pressurized Microwave Assisted Extraction. With pulp oil, impregnation yields of 58.6% were obtained by air drying, with surface area of 0.7687 m²/g, while with supercritical drying method, the impregnation yield decreased to 15.3%, with surface area of 823.4 m²/g. This indicates a loss of oil by extraction during drying. With pulp extract, the best result was obtained using indirect wet impregnation and supercritical drying, with 16.4% of impregnation. By release assay, contents of 2.276 mg/g(aerogel) of polyphenols and 0.197 mg/g(aerogel) of anthocyanins were identified., Conselho Nacional de Desenvolvimento Científico e Tecnológico – CNPq, Brazil (200737/2015-5). Doctoral scholarship, Ministerio de Economía y Competitividad (CTQ2016-79777-R)

Producción Científica, This work analyzes the influence of the mixer configuration on the mixing efficiency in the process of biomass ultrafast hydrolysis by supercritical water. The results of the CFD simulations of a horizontal tee, a vertical tee and a mixing cross, selected as the optimum mixing configurations, together with the experimental results obtained in our hydrolysis plant, are the base to determine the configuration which provides the best mixing performance. Although slightly higher conversions are obtained in those experiments performed with a horizontal tee, the small differences between the results demand a theoretical analysis. Therefore, according to the CFD simulation results, since the mixing cross provides the best flow distribution and temperature homogenization at the outlet of the mixers and because of the great similarity between the residence time distribution curves of the mixers, the mixing cross is selected as the optimum geometry to perform the mixing., Ministerio de Economía, Industria y Competitividad - FEDER (Projects CTQ2013-44143-R and CTQ2016-79777-R)

Producción Científica, In a biorefinery approach, inulin and inulin-rich biomass as Jerusalem artichoke (JA) could be transformed into platform chemicals such as fructose and/or pyruvaldehyde. To do so, the FASTSUGARS pilot plant proved to be a promising alternative for the selective conversion of biomass. In this work, inulin and JA were hydrolyzed in supercritical water (SCW) for the first time. Commercial inulin was selected as a model for fructooligosaccharides (FOS) and its reaction pathway in SCW was elucidated. It was found that fructose was the primary product from FOS hydrolysis in SCW, which was then selectively transformed into pyruvaldehyde as reaction time increased. Operating with extremely low reaction times (0.12 s) the sugars selectivity of JA was as high as 76% w/w. In both cases, the production of degradation products such as 5-HMF and acids was very low. Finally, comparing JA results to those from lignocellulosic biomass it was found that higher conversion was achieved in the case of JA due to its inulin-based composition., Ministerio de Economía, Industria y Competitividad (project CTQ2016-79777-R), Junta de Castilla y León (project VA040U16)

Producción Científica, Açaí (Euterpe oleracea Mart.) is a black-purple berry, typically found in Amazon Rainforest, and a natural phytochemical source, which shows a high content of polyphenols and flavonoids, with remarkable properties as an antioxidant, anti-inflammatory, antimicrobial, and natural dye. The precipitation and encapsulation of Açaí extracts with biopolymers by Supercritical Anti-Solvent (SAS) process were investigated and proposed as primary formulation to protect the active compounds from early degradation and its application in pharmaceutical, cosmetic, and alimentary products. The extractives were obtained from pulp and seeds by Pressurized Microwave assisted Energy (PMAE)(300 W,1.5 bar) using acidified ethanol/water (1:1v/v) as a solvent. The extracts were characterized in terms of total polyphenols content (TPC). The SAS process was carried out by semi-continuous batch at constant conditions (40 °C,100 bar). Particle morphology was studied by SEM, TGA and FTIR. The best results were obtained when ethanol and PVP were applied, obtaining a particle size reduction and an increment of TPC., Ministerio de Ciencia, innovación y Universidades (CTQ2016-79777-R), Conselho Nacional de Desenvolvimento Científico e Tecnológico – CNPq, Brazil (200737/2015-5). Doctoral scholarship

The supercritical CO2 (scCO2)-subcritical H2O (subH2O) system offers a metal- and additive-free reaction solvent that can be used for organic synthesis. The enhanced formation of carbonic acid and ionization of water under elevated pressures and temperatures promote the production of hydronium and hydroxyl ions that can catalyze the conversion of a number of organic compounds. Furthermore, the biphasic nature of the system allows for the simultaneous extraction of less polar products from the aqueous solution by a flowing scCO2 stream. In this study, we investigated the use of scCO2-subH2O as a reactive separation medium for the conversion of glucose to 5-hydroxymethylfurfural (HMF). The highest HMF yield achieved was 32.6 % with a selectivity of 52.7 %. These values corresponded to a 20.25 % and 41.9 % increase in the yield and selectivity that were achieved in the experiments performed under batch operations. The improvement was primarily attributed to the extraction of some of the HMF from the solution. The highest separation efficiency so far was 12.7 %. We also performed semi-empirical quantum calculations to determine a possible mechanism of the production of HMF from glucose. The two-step process, which involved the isomerization of glucose to fructose and the dehydration of fructose to HMF, was shown to proceed with only the OH– and H3O+ that are inherent in the solvent system as catalysts. Insights from both kinetic data and quantum calculations revealed that the reaction is highly favored in the acidic environment of the scCO2-subH2O system.

Producción Científica, Residues of the tobacco industry are a source of valuable compounds such as solanesol and nicotine. In this work, the supercritical fluid extraction of these compounds from tobacco scrap was studied. The effect of the key process parameters (pressure, temperature, extraction time) was analyzed and a phenomenological model of the extraction was applied in order to derive solubility and mass transfer coefficients. Furthermore, solanesol and nicotine obtained by supercritical extraction were fractionated by means of a liquid-liquid extraction. Results show that different conditions are required depending on the purpose of the extraction: low pressure (15 MPa) in order to enhance solanesol yield and solanesol selectivity, and high pressure (37 MPa) to promote nicotine extraction, while model results indicate that the best results were obtained in conditions in which the extraction was controlled by the solubility parameters. These results provide indications for the valorization of residues produced by the tobacco industry., Ministerio de Economía y Competitividad y Comisión Europea (FEDER) Proyecto (CTQ201679777-R), Universidad Católica de Salta (proyecto 196/18)

Supercritical water has been demonstrated as a suitable reaction media for the generation of nanomaterials. Many single and complex metal oxides can be obtained using hydrothermal synthesis techniques. This work presents a methodology to characterise continuous hydrothermal flow systems both experimentally and numerically, working at low Reynolds numbers. Under these conditions traditional computational approaches in the field are of limited use, so new tools are in demand. Residence time distributions (RTD) experiments are carried out using a purpose built continuous flow rig featuring an injection loop on the metal salt feed line, allowing injection of a chromophoric tracer. Computational fluid dynamics (CFD) calculations are also conducted using modelled geometry to represent the experimental apparatus, using a specialised approach for modelling turbulence. The performance of the CFD model is tested against the experimental data provided, verifying that the CFD model is able to predict the main flow features with good accuracy. The results indicate that the RTD profile is affected strongly by the mixing step and turbulent diffusion in the annulus section of the reactor. Different mixing regions are identified based on a mixing scale analysis. The internal RTD and its relation to the synthesis of nanomaterials is also investigated.

The efficiency of maltodextrin, whey protein isolate, and pea protein isolate to formulate a polyphenol-enriched grape marc extract by spray drying has been compared. Different inlet (120–140 °C ) and outlet (81–89 °C ) temperatures have been evaluated, as well as the amount of carrier expressed as carrier/extract ratio (0.1:1–1:1). The particles obtained were characterized in terms of their chemical composition, morphology, cytotoxicity, and cellular antioxidant activity. Outlet temperature was observed to have a higher influence on the particles than inlet temperature. A 22 % loss in total phenolic content was observed when the extract was spray dried without any carrier material, whereas the addition of the lowest amount of carrier lowered this value ( 87 %). Whey protein showed an enhancement of the chemical and cellular antioxidant activity per unit mass of gallic acid equivalent when compared to the other carriers.

The purpose of this work was to study the behavior of (1-3)(1-4)-β-D-glucan in pressurized hot water. For this purpose, solid β-glucan (450 kDa) was put in water and heated at different temperatures (120, 150, and 170°C) for different times (5 to 360 minutes). At 120°C it was found that the highest soluble β-glucan concentration was measured after 60 minutes; at 150 and 170°C optimal times were 45 and 20 minutes, respectively. The maximum amount of β-glucan dissolved in each of the optimal conditions was 1.5, 2.2, and 2.0 g/L, respectively. Under those conditions an important reduction was observed in the molecular weight: at 120°C and 60 min it was 63 kDa; at 150°C and 45 min it was reduced down to 8 kDa; and at 170°C and 20 min it was only 7 kDa. Besides this reduction in the MW some hydrolysis products, such as glucose and HMF, were observed. These results revealed the convenience of using PHW to dissolve β-glucans since the operation times, compared to the conventional process (55°C, 3 h), were reduced despite the fact that the MW was significantly reduced once the β-glucan was dissolved; therefore, PHW can be used to extract β-glucans from barley under controlled conditions in order to prevent severe degradation.

A trickle bed reactor (TBR) was used to study different process parameters upon hydrogen peroxide direct synthesis. The catalysts used were commercial palladium on active carbon. The influence of pressure (1.75–25 barg), temperature (5–60°C), liquid flow rate (2–13.8 ml·min-1), gas flow rate (3.4–58.5 ml·min-1), catalyst amount (90–540 mg), Pd percentage on the support (5% wt., 10% wt. and 30% wt. Pd/C) as well as promoter concentrations (0.0005–0.001 m) were all varied as process parameters to better understand the behaviour of the system. By contrast, the gas phase molar composition of the feed (4:20:76=H2:O2:CO2) was kept constant. The strong influence between liquid flow rate, gas flow rate and catalyst amount were identified as the key parameters to tune the reaction, and related to the activity of the catalyst. In essence, these parameters must be carefully tuned to control the hydrogen consumption. The maximum productivity (289 μmol H2O2·min-1) and yield (83.8%) were obtained when a diluted bed of 30% Pd/C was applied. The H2O2 hydrogenation was studied in order to understand its role in the H2O2 direct synthesis reaction network. The hydrogenation reaction mechanism and the role of NaBr were identified thanks to the experiment proposed in the present work. Consequently, understanding the whole reaction mechanism from the process conditions studied led to a deeper understanding of all of the phenomena involved in the H2O2 direct synthesis.

(1,3)-(1,6)-β- d -Glucans were extracted from Ganoderma lucidum (34.2%, w/w) using pressurized hot water as solvent (P = 5 MPa) in a fixed bed laboratory scale unit. A RSM Box–Behnken experimental design was used to evaluate the effect of the temperature (135–175 °C), flow rate (0.7–1.3 mL/min) and solvent to biomass ratio (20–60 mL/g) on the extraction yield of β-glucans and the content in β-glucans of the final product. A dramatic effect of the temperature was observed: the higher the temperature, the higher the extraction yield; however, at temperatures above 158 °C the β-glucan content in the final product began to decrease. It was also seen that experiments longer than 80 min are required to get the β-glucans dissolved. Finally, the effect of the flow rate on the extraction yield was not significant, indicating that external mass transport was not controlling the extraction process. The extraction conditions that maximize both extraction yield of β-glucan (64.9 ± 0.8%) and led to the highest content in β-glucans in the final product (61.7 ± 1.0%) are 158 °C, 1.3 mL/min and 60 mL/g. The addition of supercritical CO2 to the pressurized hot water throughout the extraction (done at 155 °C, 1 mL/min of PHW and 40 mL/g) produced a significant improvement of the extraction yield up to 72.5% in the best tested conditions; effect primarily attributed to the acidification of the media obtained by the supercritical CO2.

The hydrolytic hydrogenation of cellulose was studied using mesoporous Ru/MCM-48 as a catalyst. Supercritical water (SCW) was used as a reaction medium for cellulose hydrolysis, since in this reaction medium it is possible to depolymerize cellulose with a high selectivity towards sugars (70% w/w), avoiding degradation reactions when extremely low reaction times are used. The SCW hydrolysis was carried out at 400 °C – 25 MPa and 0.20 s. The hydrogenation of the liquid product from cellulose hydrolysis in SCW was further studied by changing the temperature and reaction time to maximize the yield of hexitols. The results demonstrated the achievement of higher yields of hexitols by the subsequent hydrogenation of the liquid product from cellulose hydrolysis in SCW (49%) rather than using a one-pot catalytic hydrogenation process. Ru/MCM-48 showed better behavior than commercial Ru/C during the hydrogenation process in all cases. Ru/MCM-48 was also employed in the hydrogenation of the product from sugar beet pulp (SBP) hydrolysis in SCW. SBP was used in order to evaluate the behavior of real biomass in this process. A 15% yield of hexitols was achieved from SBP, where ethylene glycol was the main compound in the liquid product and glycerol was obtained as a byproduct too.