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A biorefinery approach to obtain antioxidants, lignin and sugars from exhausted olive pomace
(Elsevier, 2021-01-30) Gómez-Cruz , Irene; Contreras Gámez, María del Mar; Romero , Inmaculada; Castro , Eulogio
Exhausted olive pomace (EOP) is the main residue of the pomace olive oil extracting industry. In this work, EOP was fractionated into valuable components for valorisation: an aqueous extract rich in hydroxytyrosol and mannitol, lignins with antioxidant properties and fermentable sugars. EOP was first subjected to water extraction at 85 °C for 90 min. Several pretreatments based on liquid hot water and organosolv with 50% or 60% ethanol (catalysed and uncatalysed with 1% sulfuric acid) were then evaluated in terms of delignification ability and efficiency for enzymatic hydrolysis of the pretreated solids. Once the best conditions had been selected (50 % ethanol-1% sulfuric acid at 130 °C for 60 min), an organosolv lignin (OL) with antioxidant properties was obtained through acid precipitation of the pretreatment liquor. This was compared to the enzymatic hydrolysis lignin obtained in the subsequent step and to the lignins purified by acid hydrolysis. OL showed a higher total phenolic content and antioxidant activity than the rest of the lignin samples. Chemical differences were also observed that could explain the results.
A numerical and experimental study of the compression uniaxial properties of PLA manufactured with FDM technology based on product specifications
(Int J Adv Manuf Technol. 103, pages1893–1909 (2019), 2019-04-13) Mercado-Colmenero, Jorge Manuel; Rubio-Paramio, Miguel Ángel; La Rubia-García, M.Dolores; Lozano-Arjona, David; Martin-Doñate, Cristina
This paper presents a numerical and experimental study of the compression uniaxial properties of PLA material manufactured with FDM based on product specifications. A first experimental test in accordance with the requirements and conditions established in the ISO 604 standard characterizes the mechanical and elastic properties of PLA manufactured with FDM technology and product requirements in a uniaxial compression stress field by testing six specimens. A second experimental test allows analyzing the structural behavior of the industrial case, evaluating the compression stiffness, the compression yield stress, the field of displacements, and stress along its elastic area until reaching the compression yield stress and the ultimate yield stress data. To improve the structural analysis of the case study, a numerical validation was carried out using two analytical models. The first analytical model applies an interpolation procedure to the experimental results of the tested specimens in order to characterize the uniaxial tension-compression curve versus the nominal deformations by means of an 8-degree polynomial function. The second model defines the plastic material as elastic and isotropic with Young’s compression modulus constant and according to the guidelines established in ISO standard 604. The comparison between experimental tests and numerical simulation results for the study case verify that the new model that uses the proposed polynomial function is closer to the experimental solution with only an 0.36% error, in comparison with the model with Young’s compression modulus constant that reaches an error of 4.27%. The results of the structural analysis of the mechanical element indicate that the elastic region of the plastic material PLA manufactured with FDM can be modeled numerically as an isotropic material, using the elastic properties from the experimental results of the specimens tested according to ISO standard 604. In this way, it is possible to characterize the PLA FDM material as isotropic, obtaining as an advantage its easy definition in the numerical simulation software as it does not require the modification of the constitutive equations in the material database. SEM micrographs have indicated that the fracture of the failed test specimens is of the brittle type, mainly caused by the separation between the central plastic filament layers of the specimens. The results presented suggest that the use of FDM technology with PLA material is promising for the manufacture of low volume industrial components that are subject to compression efforts or for the manufacture of components by the user.
ACE-inhibitory and antihypertensive properties of a bovine casein hydrolysate
(Elsevier Ltd., 2009-01-01) Miguel, Marta; Contreras, María del Mar; Recio, Isidra; Aleixandre, Amaya
The aim of this study was to investigate the potential angiotensin converting enzyme (ACE)-inhibitory activity and the antihypertensive effect, after a single oral administration, of a pepsin hydrolysed bovine casein (HBC) and a fraction with molecular mass lower than 3000 Da (HBC < 3000). ACE-inhibitory activity was measured by spectrophotometric assay. These products were orally administered by gastric intubation. The systolic (SBP) and the diastolic blood pressure (DBP) were measured in spontaneously hypertensive rats by the tail cuff method before administration and also 2, 4, 6, 8, and 24 h post-administration. HBC showed a potent ACE-inhibitory activity. This activity was 10 times higher in HBC < 3000. HBC and HBC < 3000 decreased the arterial blood pressure of the rats. The decrease in the SBP observed for HBC (400 mg/kg) or HBC < 3000 (200 mg/kg) was less pronounced than that caused by 50 mg/kg of captopril (antihypertensive positive control). However, the maximal decreases in DBP caused by HBC or HBC < 3000 were as high as the maximum decrease observed for captopril. The antihypertensive effect of these products was transient and reverted 24 h after the administration. HBC and HBC < 3000 exert antihypertensive effect caused by small peptides with ACE-inhibitory activity.
Acute and repeated dose (4 weeks) oral toxicity studies of two antihypertensive peptides, RYLGY and AYFYPEL, that correspond to fragments (90–94) and (143–149) from αs1-casein
(Elsevier Ltd., 2010-07) Anadón, Arturo; Martínez-Caballero, María Aranzazu; Ares, Irma; Ramos-Alonso, Eva; Martínez-Larrañaga, María Rosa; Contreras-Gámez, María Mar; Ramos-González, Mercedes; Recio, Isidra
The Lowpept® is a powdered casein hydrolysate containing the antihypertensive peptides RYLGY and AYFYPEL, two sequences that correspond to αs1-casein f (90–94) (RYLGY) and αs1-casein f (143–149) (AYFYPEL). To support the safety, Lowpept® has been examined in an acute and in a 4-week repeated dose oral toxicity studies in rats. Powdered casein hydrolysate administered in a single oral gavage dose of 2000 mg/kg resulted in no adverse events or mortality. Also, casein hydrolysate administered as a daily dose of 1000 mg/kg for 4 weeks by gavage resulted in no adverse events or mortality. No evidence or treatment-related toxicity was detected during both studies. Data analysis of body weight gain, food consumption, clinical observations, blood biochemical, haematology, organ weight ratios and histopathological findings did not show significant differences between control and treated groups. It is concluded that the casein hydrolysate containing the peptides RYLGY and AYFYPEL orally administered to rats was safe and that not treatment-related toxicity was detected even at the highest doses investigated in both acute (2000 mg/kg of body weight) and repeated dose (4 weeks) oral (1000 mg/kg of body weight) toxicity studies.
Alkaline activated cements obtained from ferrous and non-ferrous slags. Electric arc furnace slag, ladle furnace slag, copper slag and silico-manganese slag
(Elsevier, 2024-03) Gómez-Casero , Miguel A.; Bueno Rodríguez, Salvador; Castro, Eulogio; Eliche Quesada, Dolores
Ferrous slag: electric arc furnace slag (EAFS) and ladle furnace slag (LFS); and non-ferrous slag: copper slag (CS) and silicon-manganese slag (SiMnS) have been used as precursors for alkali activated cements (AACs). The objective of the study was to evaluate the effect of the silica modulus (Ms = SiO2/K2O) (0.5–1.8) of the potassium silicate/potassium hydroxide solution on the microstructure and technological properties of AACs using individual slags. The results obtained indicate that under the activation conditions used, CS and EAFS are more reactive slags, giving rise to AACs with optimum flexural and compressive strengths of 7.5 and 51.5 MPa and 5.7 and 30.5 MPa for a Ms = 1.4, respectively. While the SiMnS and LFS are less reactive resulting in AACs with flexural and compressive strengths of 3.2 and 11.6 MPa at Ms = 1.4 for SiMnS and 1.1 MPa and 4.6 MPa at Ms = 0.9 for LFS. In all AACs, the development of the alkaline activation reaction is confirmed due to the presence of gel, of different nature and quantity depending on the precursor used. The lower mechanical properties of the AACs using SiMnS and LFS as precursor may also be due to the presence of microcracks. Therefore, this study confirms that ferrous and non-ferrous slags can be used as precursors of AACs, with the type of precursor and the modulus of the activating solution influencing mechanical properties. AACs using CS and EAFS can be used in structural applications, while those using SiMnS and LFS can be used in non-structural applications in civil engineering.
An integrated olive stone biorefinery based on a 1 two-step fractionation strategy
(Elsevier, 2022) Padilla-Rascón, Carmen; Carvalheiro, Florbela; Duarte, Luís C.; Roseiro, Luisa B.; Ruiz, Encarnación; Castro, Eulogio
Olive stones (OS) constitute a waste lignocellulosic material produced by the olive oil industry in great amounts, that currently is only used as a low-value energy source for industrial or domestic boilers. Having in view its full valorization, this work proposes and validates an integrated strategy aiming to obtain three different streams of sugars / lignin-derived compounds. Dilute acid hydrolysis was used to obtain a xylose-rich hydroysate that was chemically converted into furfural with a 48.7 % yield. The resulting acid-pretreated solid biomass that consisted mainly of lignin and cellulose, was subjected to a catalyzed ethanol-based organosolv delignification. Temperature, time, and sulphuric acid concentration were optimized in order to recover added-value lignin products and digestible cellulose. At the optimal conditions (190 ᵒC and 30 min), a 50 % delignification was reached, together with the highest enzymatic hydrolysis yields (190 g glucose/kg of OS). Phenolic compounds content in organosolv liquors reached 41.6 mg GAE/g OS. This extract presented an antioxidant capacity up to 10.9 mg TE/g OS. The pretreated solid fraction was used as a substrate for ethanol production by a pre-saccharification and simultaneous saccharification and fermentation process, enabling to obtain an ethanol concentration of 47 g/L, with a fermentation yield of 61.4% of the theoretical maximum. Globally, from 100 kg of OS processed according to this experimental scheme, 6.9 kg of furfural, 6.2 kg of ethanol, 7.4 kg of lignin, and 4.2 kg of phenolics compounds can be obtained as main products, thus constituting a way of valorization of renewable material in a multiproduct biorefinery strategy.
Análisis del proceso de extracción de antioxidantes del hueso de oliva
(Universidad de Cuenca, Facultad de Ciencias Químicas (Ecuador), 2015-11-27) Hernández, Valentina; Idárraga, Ángela M.; Cerón, Ivonne X.; Romero-García, Juan M.; Castro, Eulogio; Dávila, Javier A.; Cardona, Carlos A.
Olive tree cultivation is spreading worldwide due to the beneficial effects of olive oil consumption. Olive oil production process and table olive industries are the major sources of olive stones. Currently, this by-product is used in direct combustion to produce energy as electricity or heat. However, there are other possibilities for taking full advantage of this renewable source, and its recovery would represent an economic improvement for farmers.The olive stone not only contains primarily lignocellulosic, but also it has revealed the presence of phenolic compounds with antifungal and antibacterial properties. For this reason, in this work the extraction of antioxidant compounds is proposed as a process with supercritical fluids for olive stone. These bioactive molecules can be used in the food industry, cosmetics, functional foods, and nutraceuticals additives. During the analysis of percent inhibition of DPPH method, an antioxidant capacity of 5.63 mg trolox equivalent (TE) per g dry matter was found.
Analyzing the Role of Fe0 and Fe3+ in the Formation of Expanded Clay Aggregates
(MPDI, 2023-08-14) Moreno-Maroto, González-Corrochano, B. J.M.; Martínez-Rodríguez, Conde-Sánchez, A.; Cobo-Ceacero, Alonso-Azcárate, J. C.J.; Uceda-Rodríguez, López García, A.B. M.; Martínez-García, Cotes-Palomino, T C.
The effect of the addition of Fe0 and Fe3+ on the formation of expanded clay aggregates was studied using iron-free kaolin as an aluminosilicates source. Likewise, the incorporation of cork powder as a source of organic carbon and Na2CO3 as a flux in the mixtures was investigated in order to assess its effect in combination with the iron phases. An experimental protocol, statistically supported by a mixture experiments/design of experiments approach, was applied to model and optimize the bloating index, density, absorption capacity, and mechanical strength. The process of expansion and pore generation and the associated decrease in density required the addition of iron, such that the optimum mixtures of these properties presented between 25 and 40 wt.% of Fe0 or Fe3+, as well as the incorporation of 3.5–5 wt.% of organic carbon. The addition of Fe3+ produced a greater volumetric expansion (max. 53%) than Fe0 (max. 8%), suggesting that the formation of the FeO leading to this phenomenon would require reducing and oxidizing conditions in the former and the latter, respectively. The experimental and model-estimated results are in good agreement, especially in the aggregates containing Fe0. This reinforces the application of statistical methods for future investigations.
Application of mass spectrometry to the characterization and quantification of food-derived bioactive peptides
(Oxford University Press, 2008-07-01) Contreras, María del Mar; López-Expósito, Iván; Hernández-Ledesma, Blanca; Ramos, Mercedes; Recio, Isidra
Biologically active peptides are of particular interest in food science and nutrition because they have been shown to play different physiological roles, including antihypertensive, opioid, antimicrobial, and immunostimulating activities. Because these peptides are generated by protein hydrolysis or fermentation, they can represent only minor constituents in a highly complex matrix and therefore, identification of biologically active peptides in food matrixes is a challenging task in food technology. In this context, mass spectrometry (MS) has developed into a necessary tool to assess quality and safety of food and, more recently, to determine the presence and behavior of functional components such as these bioactive peptides. This review highlights the existing methods based on MS to identify, characterize, and quantify food-derived biologically active peptides, taking into account the different ionization sources used for the analysis of these high-value food components. The quantitative determination of bioactive peptides in food products or biological fluids is also discussed.
Biological hydrogen and furfural production from steam-exploded vine shoots
(ELSEVIER, 2023-10-03) Castro, E.; Silva Rabelo, C.; Padilla-Rascón, C.; Vidal, A.; López-Linares, J.C.; Vasreche, M.B.; Romero, I.
Vine shoots are an agricultural waste rich in carbohydrates that can be considered as a promising energy source alternative. The objective of this work was to propose a process strategy for the valorisation of this residual biomass, including the chemical conversion of solubilised sugars into furfural and the biological conversion of cellulosic glucose into H2. Vine shoots were subjected to steam explosion pretreatment, and its operational conditions were optimised as 190 ◦C and 1.6% H2SO4 impregnated biomass. These pretreatment conditions allowed to recover 68.2% of the hemicellulose sugars and 18.2% of glucose in the prehydrolysate and 45.3% glucose by enzymatic hydrolysis. Thus, the pretreated solid obtained under optimised conditions was subjected to enzymatic hydrolysis and the slurry generated was used as a substrate by Clostridium butyricum for fermentation into biohydrogen (830.7 mL/L and a yield of 3550 mL per 100 g of raw vine shoots) and organic acids (1495.3 mg acetic acid/L and 1726.8 mg butyric acid/L). Based on furfural production, the chemical conversion of xylose in the prehydrolysate was optimised in a microwave reactor at 202 ◦C, using 0.195 M FeCl3 as a catalyst, with a furfural production of 15 g/L and 73% yield.
Biological hydrogen and furfural production from steam-exploded vine shoots
(Elsevier, 2023) Castro, Eulogio; Rabelo, Camila A.B.S.; Padilla-Rascón, Carmen; Vidal, Alfonso M.; López-Linares, Juan Carlos; Varesse, Maria B.A.; Romero, Inmaculada
Vine shoots are an agricultural waste rich in carbohydrates that can be considered as a promising energy source alternative. The objective of this work was to propose a process strategy for the valorisation of this residual biomass, including the chemical conversion of solubilised sugars into furfural and the biological conversion of cellulosic glucose into H2. Vine shoots were subjected to steam explosion pretreatment, and its operational conditions were optimised as 190 ºC and 1.6% H2SO4 impregnated biomass. These pretreatment conditions allowed to recover 68.2% of the hemicellulose sugars and 18.2% of glucose in the prehydrolysate and 45.3% glucose by enzymatic hydrolysis. Thus, the pretreated solid obtained under optimised conditions was subjected to enzymatic hydrolysis and the slurry generated was used as a substrate by Clostridium butyricum for fermentation into biohydrogen (830.7 mL/L and a yield of 3,550 mL per 100 g of raw vine shoots) and organic acids (1,495.3 mg acetic acid/L and 1,726.8 mg butyric acid/L). Based on furfural production, the chemical conversion of xylose in the pre-hydrolysate was optimised in a microwave reactor at 202 ºC, using 0.195 M FeCl3 as a catalyst, with a furfural production of 15 g/L and 73% yield.
Bioreﬁnery based on olive biomass. State of the art and future trends
(Elsevier, 2014-03-25) Romero-García, Juan Miguel; Niño, Luis; Martínez-Patiño, José Carlos; Álvarez-Vaquerizo, Cristina; Castro-Galiano, Eulogio; Negro, María José
With currently more than nine million hectares, olive tree cultivation has spread worldwide, table olives and olive oil as the main products. Moreover, a number of by-products and residues derived from both tree cultivation and the process of industrial olive oil production, most having no practical applications, are obtained yearly. This paper reviews the research regarding these by-products, namely biomass from olive tree pruning, olive stones, olive pomace and wastewaters obtained from the process of olive oil production. Furthermore, a wide range of compounds has been identified and can be produced using a broad definition of the term biorefinery based on olive tree biomass. As an example, this paper reviews ethanol production as one of the main proposed applications, as well as research on other value-added products. Finally, this paper also assesses recent technological advances, future perspectives and challenges in each stage of the process.
Biorefining for olive wastes management and efficient bioenergy production
(Elsevier, 2021) Najafi, Elham; Castro, Eulogio; Karimi, Keikhosro
The potential of olive wastes for development of a multi-product biorefinery was investigated. Different parts of olive wastes, i.e., stone, pomace, leaves, and wood, were subjected to liquid hot water, organosolv, and acid-catalyzed organosolv (ACO) pretreatments prior to bioconversion through three different scenarios. The first scenario, i.e., anaerobic digestion of substrates for biogas production, yielded 219.3 m3 biomethane per hectare of olive trees, equated to 247.4 L gasoline. The highest methane production of 103.3 m3 was attributed to liquid hot water pretreated wood and ACO increased methane yield for leaf and stone samples by 200 and 33%, respectively. The second scenario, i.e., fermentation of wastes for bioethanol production, resulted in 295.9 L bioethanol per hectare of olive trees, equivalent to 196.1 L gasoline. Organosolv pretreated wood with 82.9% production yield and 152.5 L bioethanol constitutes this plan's dominant part. The ACO pretreatment improved fermentation yield for pomace and stone samples by 49% and 53%, respectively. The third scenario, included the utilization of olive wastes in bioethanol production, anaerobic digestion of fermentation residues, and lignin separation, resulted in 295.9 L bioethanol, 137.2 m3 biomethane, and 347.1 kg lignin, equated with 521.6 L gasoline. Furthermore, the remaining oil content in pomace and stone samples was 17% and 20%, respectively, which could be used for biodiesel production. Overall, olive wastes processing through an integrated biorefinery plant with multiple products significantly improved the energy recovery of the whole plant.
Can statistical methods optimize complex multicomponent mixtures for sintering ceramic granular materials? A case of success with synthetic aggregates
(ELSEVIER, 2023-07-15) Moreno-Maroto, José Manuel; Conde-Sánchez, Antonio; González-Corrochano, Beatriz; Uceda, Manuel; Martínez-García, Carmen; Cobo-Ceacero, Carlos Javier; Martínez-Rodríguez, Ana María; Alonso-Azcárate, Jacinto; López-García, Ana Belén; Cotes, Teresa
The relationship between the proportions of multicomponent mixtures with the technological properties of ceramic granular materials (synthetic aggregates) has been studied using statistical methods. The four phases involved in the formulations have been: kaolin (K) as aluminosilicate source; cork powder (C) as organic carbon source; sodium carbonate (N) as flux and pyrite (P) as source of iron and sulfur. The Mixture Experiments - Design of Experiments (ME-DOE) has been the statistical methodology applied from the initial configuration of the 36 starting formulations to the final validation of the models and optimums. After granulation, artificial aggregates have been obtained by sintering in a rotary kiln, and their main technological properties have been determined. Bloating index (BI), particle density (ρrd), water absorption (WA24) and crushing strength (S) were selected as the four key characteristics to be modeled and optimized, using response surface and effect plots to assess the effect of K, C, N and P on such properties. 32 out of 36 starting varieties met the density criteria for lightweight aggregates. In the optimum formulations obtained, the minimum percentage of K was 83 wt%, so that the variations in the percentages of P, C and N were the critical variables for determining the final properties of the aggregate. The contrast between experimental and estimated data has shown that the models fit adequately, indicating that this type of approach may have enormous potential for future research on artificial aggregates and other ceramic materials.
Carbon-negative products to engage society in climate action: The life cycle of olive oil
(Elsevier Ltd, 2024-04-22) Galán-Martín, Ángel; Contreras, María del Mar; Castro, Eulogio
Achieving carbon neutrality and addressing the need for ongoing carbon dioxide removal to meet the climate goal requires an urgent shift towards sustainable production and consumption practices. In this context, we turn our attention to the olive oil industry, a key food industry that strives towards more environmentally sustainable initiatives. Our study explores a novel approach that integrates bioenergy with carbon capture and storage (BECCS) into olive oil production. Employing Life Cycle Assessment, we assess the potential for carbon-negative olive oil production and its broader environmental implications. Our findings demonstrate that producing carbon-negative virgin olive oil is possible by powering the olive mill processes with BECCS based on olive prunings generated at the agricultural stage (up to −0.32 kg CO2eq per 1-l bottle of virgin olive oil). However, collateral damages to acidification and eutrophication will also emerge, which can be mitigated through careful project planning tailored to local conditions. The path forward involves strategic investments, customized policies, collaboration between public and private sectors, and consumers' willingness to support carbon offset projects. Our work may contribute to unlocking the full potential of BECCS, offering a blueprint for other industries beyond the realm of olive oil production, ultimately catalyzing the realization of carbon-negative products.
Cellulose-Based Upcycling of Brewer´s Spent Grains: Extraction and Acetylation
(Springer, 2023-11-11) Camacho-Núñez, L.; Jurado-Contreras, S.; La Rubia, M.D.; Navas-Martos, F.J; Rodríguez-Liébana, J.A
As the main byproduct of beer production, huge amounts of brewer´s spent grain (BSG) are generated annually worldwide. BSG is being currently underutilized since they are mostly devoted to animal feeding. Nevertheless, BSG offers a wide range of upcycling possibilities due to its lignocellulosic nature. In this work, we have addressed the extraction of cellulose and its further conversion into cellulose acetate, a biodegradable polymer with potential industrial application, especially as food contact material. The effectiveness of both processes, cellulose extraction and acetate synthesis were monitored by performing a comprehensive physicochemical characterization of the products. The influence of reaction time (1–5 h) on acetylation extent and acetate properties was also assessed. The results reflected that the process effectively removed hemicelluloses and lignin from BSG, and yielded a cellulose pulp with 63% crystallinity and 351 °C maximum degradation temperature. However, around 28% of the cellulose was solubilized, with acid pretreatment as the most aggressive step (above 19% disappearance). Acetylation extent was practically not affected by reaction time, and cellulose acetate with degree of substitution approximately 2.60 was obtained already after 1 h. Infrared spectra and X-ray diffractograms were similar for all acetate samples. Nevertheless, the thermogravimetric analysis evidenced that at least 3 h were needed to obtain a product with high thermal stability. This work addressed for the first time the acetylation of cellulose isolated from BSG, and may serve as basis for the manufacturing of a biobased plastic with application in sectors such as food packaging.
Combined Extraction and Ethanol Organosolv Fractionation of Exhausted Olive Pomace for Bioactive Compounds
(Wiley Online Library, 2022-01-25) Gómez-Cruz , Irene; Romero, Inmaculada; Contreras Gámez , María del Mar; Labidi, Jalel; Hernández-Ramos, Fabio; Roseiro, Luisa B.; Duarte, Luis C.; Castro , Eulogio; Carvalheiro, Florbela
The olive pomace oil extracting industry generates large amounts of exhausted olive pomace (EOP), a lignocellulosic waste that needs to be managed according to sustainable criteria. The aim of this work is to devise an integrated strategy to valorize EOP by applying two-step extraction, and to evaluate the effect of an ethanol organosolv pretreatment on the delignification and enzymatic hydrolysis of the extracted EOP. Once the extraction and organosolv pretreatment conditions are selected, solubilized lignin is recovered from the pretreatment liquor using different methods. In addition to those organosolv lignin samples, a lignin-rich solid is obtained after enzymatic saccharification of the pretreated solid. All the lignin samples are fully characterized aiming at further valorization. The selected two-step aqueous extraction (85 °C, 90 min, 10% biomass) removes 89% of the extractives content in raw EOP and achieves the full recovery of phenols and mannitol content in that fraction, 4.7 mg gallic acid equivalents per g EOP and 4.5 mg g−1 EOP, respectively. The organosolv pretreatment (50% ethanol catalyzed with 1% H2SO4, 140 °C, 60 min, 15% biomass) results in a delignified solid with 81% of enzymatic digestibility and a high purity organosolv lignin (>71%), rich in guaiacyl units.
Comparative Life Cycle Assessment of Lightweight Aggregates Made from Waste—Applying the Circular Economy
(MPDI, 2022-02-12) Uceda-Rodríguez, Moreno-Maroto, J.M. M.; Cobo-Ceacero, López-García, A.B. C.J.; Cotes-Palomino, Martínez-García, C T.
Abstract The application of Life Cycle Assessment in the construction sector can be a very useful tool to reduce the environmental impact generated by the sector. In order to quantify the improvement in environmental terms with the use of artificial lightweight aggregates (LWA) manufactured with waste, in this work, we conducted a comparative evaluation of the life cycle of LWAs for a total of five different scenarios: LWAs obtained in a traditional way, i.e., using exclusively clay in their manufacture (Spanish blond clay, Portuguese red clay and Portuguese blond clay), and LWAs manufactured with four different wastes, with a partial substitution of 2.5% for each of the clays per waste (almond and hazelnut shells, sludge from the purification of paper money, cork dust and coffee grounds). The functional unit was set as the production of 1 kilo of lightweight aggregates and the CML 2000 methodology and the SimaPro software were used. The results obtained in this research allow us to conclude that the addition of organic wastes showed a slightly higher environmental performance than the conventional system, the ALAs manufactured with almond and hazelnut shells being the most environmentally friendly option, with reductions of more than 30% in some cases, followed by the LWAs manufactured with coffee grounds. On the other hand, the addition of paper sewage sludge and cork dust represents minimal environmental optimization.
Deep eutectic solvents for improved biomass pretreatment: Current status and future prospective towards sustainable processes
(Elsevier Ltd, 2022-11-26) Contreras-Gámez, María del Mar; Galán-Martín, Ángel; Seixas, Nalin; da Costa Lopes, André M.; Silvestre, Armando; Castro, Eulogio
Pretreatment processes — recognized as critical steps for efficient biomass refining — have received much attention over the last two decades. In this context, deep eutectic solvents (DES) have emerged as a novel alternative to conventional solvents representing a step forward in achieving more sustainable processes with both environmental and economic benefits. This paper presents an updated review of the state-of-the-art of DES-based applications in biorefinery schemes. Besides describing the fundamentals of DES composition, synthesis, and recycling, this study presents a comprehensive review of existing techno-economic and life cycle assessment studies. Challenges, barriers, and perspectives for the scale-up of DES-based processes are also discussed.
Delignification of Olive Tree Pruning Using a Ternary EutecticSolvent for Enhanced Saccharification and Isolation of a UniqueLignin Fraction
(ACS Publications, 2024-09-30) Gómez-Cruz , Irene; Nalin, Seixas; Labidi, Jalel; Castro, Eulogio; Silvestre, Armando J.D.; da Costa Lopes, André
This work aimed at exploring the potentialities of eutectic solvents (ES) in the fractionation of olive tree pruning (OTP) biomass within a biorefinery framework, targeting efficient separation of cellulose fibers and lignin and simultaneously producing high-quality fractions for further processing and application. In this sense, delignification performances of cholinium chloride:ethylene glycol, ChCl:EG (1:9) and cholinium chloride:p-toluenesulfonic acid:ethylene glycol, ChCl:pTSA:EG (1:1:9) as binary and ternary mixtures, respectively, were first evaluated. ChCl:EG demonstrated low efficacy for biomass delignification, while the highest lignin extraction (62.7%) was achieved with ChCl:pTSA:EG at 80 °C and 4 h. At the same conditions, the cellulose content (62.5%) of the resulting solid fraction increased almost three-fold compared to that of the raw OTP (22.3%), using ChCl:pTSA:EG. This ternary ES enabled the OTP matrix breakdown, which, combined with lignin extraction, enhanced the enzymatic hydrolysis of the cellulose-rich fraction to a maximum saccharification yield of 81.8%. The sample exhibited an impressive aliphatic OH group content of 5.2 mmol·g–1 lignin, one of the highest values among the state-of-the-art. The resulting phenomenon is explained by the ethylene glycol grafting onto the lignin structure (aliphatic region), as demonstrated by 31P and HSQC NMR, giving chemical functionality to the isolated lignin fraction. Finally, up to 90% of the initial mass of ChCl:pTSA:EG was recovered through the adsorption of impurities. NMR data validated the high purity and the same molar ratio (1:1:9) of recovered ES, two important outcomes to ensure a sustainable reutilization of this solvent.

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