Microwave-assisted extraction of hemicellulosic oligosaccharides and phenolics from Robinia pseudoacacia wood

Financiaciado para publicación en acceso aberto: Universidade de Vigo/CISUGMicrowave-assisted autohydrolysis is an environmentally friendly intensification technology that permits the selective solubilization of hemicelluloses in form of oligosaccharides in a short time and with low energy consumption. The purpose of this work was to evaluate the suitability of microwave-assisted autohydrolysis to produce oligosaccharides and phenolics with potential prebiotic and antioxidant activities from Robinia pseudoacacia wood. The influence of treatment time (0–30 min) and temperature (200–230 ◦C) on oligosaccharide production was studied and conditions of 230 ◦C and 0.25 min resulted in maximum content of xylooligosaccharides (7.69 g XO/L) and more efficient energy consumption. Furthermore, under those conditions, liquors showed high contents of phenols (80.28 mg GAE/g of RW) and flavonoids (44.51 RE/g) with significant antioxidant activities (112.07 and 102.30 mg TE/g, measured by ABTS and FRAP tests, respectively). Additionally, the solubilized hemicelluloses were structurally characterized by HPAEC-PAD, MALDI-TOF-MS, FTIR and TGA/DSC, and HPLC-ESI-MS analysis allowed the tentative identification of 17 phytochemicals.Ministerio de Economía y Competitividad | Ref. PID2019-110031RB-I00Xunta de Galicia | Ref. ED431C 2017/62-GRCMinisterio de Ciencia e Innovación | Ref. FPU21/02446Ministerio de Ciencia e Innovación | Ref. PRE 2020 093359Ministerio de Ciencia e Innovación | Ref. RYC2018-026177-IXunta de Galicia | Ref. ED481B-2022-02

Synergetic effect of hydrothermal and deep eutectic solvents (DES) pretreatments on Robinia wood fractionation for the manufacture of bioethanol and cellulose nanocrystals

This study dealt with the use of environmentally friendly processes based on microwave-assisted autohydrolysis (MAA) and deep eutectic solvents (DES) for the selective fractionation of Robinia pseudoacacia wood (RW) within a biorefinery approach. MAA enabled the recovery of 76% of hemicelluloses in the form of oligomers. Afterwards, different conditions were assessed for the optimal delignification of RW with the DES choline chloride combined with lactic acid reaching delignification ratios up to 86%. Two different methods were accomplished to valorize the cellulosic-rich solid fraction after delignification: (i) bioethanol via enzymatic-fermentative pathway (attaining 53.3 g ethanol/L, about 83% of ethanol yield), and (ii) cellulose nanocrystals (length of 27–550 nm, width of 2–12 nm). Hence, this study presents a novel multiproduct biorefinery to selectively separate the main components of RW and valorize its cellulosic fraction using eco-friendly proceduresUniversidade de Vigo/CISUGMinisterio de Economía| Ref. PID2019-110031RB-I00Xunta de Galicia | Ref. ED431C 2017/62-GRCMinisterio de Ciencia, Innovación y Universidades | Ref. FPU21/02446Ministerio de Ciencia, Innovación y Universidades | Ref. PRE2020-093359Ministerio de Ciencia, Innovación y Universidades | Ref. RYC2018-026177-IXunta de Galicia | Ref. ED481B-2022-02

Eco-friendly strategy for the joint valorization of invasive macroalgae and fast-growing wood to produce advanced biofuels

A novel sustainable scheme to jointly valorize Sargassum muticum (Sm) and Paulownia wood (PW) was proposed in this work, employing the advanced environmentally friendly microwave-assisted autohydrolysis (MA) as pretreatment. Sm is an invasive macroalga that has been drastically spread in the Atlantic coast of Europe, causing environmental damage. Conversely, Paulownia elongata x fortunei is a fast-growing biomass with a high biomass production and potential for biofuels production. Thus, the concomitant valorization of both biomasses may lead to benefits related to environmental protection and bioeconomy. A sequential approach was proposed: first stage of glucose production from Sm (treated by MA and enzymatic hydrolysis to obtain a glucose-rich liquor), and second stage with MA-pretreated PW followed by saccharification and fermentation, employing in this process the glucose rich solution obtained from algae, to obtain simultaneously second and third generation bioethanol. These approaches enabled to add the ethanol production from both biomasses, leading to up to 45.2 g ethanol/L (70% ethanol yield), boosting ethanol titers compared to using only one biomass (up to 27.8 g/L) and confirming the benefits of combining MA-processed biomass. Furthermore, up to 87% of the energy may be recovered, reflecting a suitable approach within an integrated strategy.Agencia Estatal de Investigación | Ref. PID2019-110031RB-I00Agencia Estatal de Investigación | Ref. CNS2022-136095Xunta de Galicia | Ref. ED431C 2017/62-GRCXunta de Galicia | Ref. ED481B-2022-020Agencia Estatal de Investigación | Ref. RYC2018-026177-IAgencia Estatal de Investigación | Ref. RYC2020-030690-IUniversidade de Vigo/CISU

Hemicellulosic bioethanol production from fast-growing Paulownia biomass

In order to exploit a fast-growing Paulownia hardwood as an energy crop, a xylose-enriched hydrolysate was obtained in this work to increase the ethanol concentration using the hemicellulosic fraction, besides the already widely studied cellulosic fraction. For that, Paulownia elongata x fortunei was submitted to autohydrolysis treatment (210 °C or S0 of 4.08) for the xylan solubilization, mainly as xylooligosaccharides. Afterwards, sequential stages of acid hydrolysis, concentration, and detoxification were evaluated to obtain fermentable sugars. Thus, detoxified and non-detoxified hydrolysates (diluted or not) were fermented for ethanol production using a natural xylose-consuming yeast, Scheffersomyces stipitis CECT 1922, and an industrial Saccharomyces cerevisiae MEC1133 strain, metabolic engineered strain with the xylose reductase/xylitol dehydrogenase pathway. Results from fermentation assays showed that the engineered S. cerevisiae strain produced up to 14.2 g/L of ethanol (corresponding to 0.33 g/g of ethanol yield) using the non-detoxified hydrolysate. Nevertheless, the yeast S. stipitis reached similar values of ethanol, but only in the detoxified hydrolysate. Hence, the fermentation data prove the suitability and robustness of the engineered strain to ferment non-detoxified liquor, and the appropriateness of detoxification of liquor for the use of less robust yeast. In addition, the success of hemicellulose-to-ethanol production obtained in this work shows the Paulownia biomass as a suitable renewable source for ethanol production following a suitable fractionation process within a biorefinery approach.This research was funded by MINECO (Spain) in the framework of the projects “Multistage processes for the integral benefit of macroalgal and vegetal biomass” with reference CTM2015-68503- R,” and “Cutting-edge strategies for a sustainable biorefinery based on valorization of invasive species” with reference PID2019-110031RB-I00, to Consellería de Cultura, Educación e Ordenación Universitaria (Xunta de Galicia) through the contract ED431C 2017/62-GRC to Competitive Reference Group BV1, program partially funded by European Regional Development Fund (FEDER). This study was also supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit.info:eu-repo/semantics/publishedVersio

Bioethanol production from autohydrolyzed Sargassum muticum

Currently, the high demand of energy has led to the seek of new renewable sources, cutting down with fossil fuels. An interesting and novel way may be the use of macoralgae as raw material to obtain third generation bioethanol. Sargassum muticum is an invasive seaweed highly spread in Asia, Europe and America, which has not been commercially used yet. It has an abundant quantity of polysaccharides which can be used in the production of biofuels. In order to employ them, it is necessary to pretreat the material, and the hydrothermal treatments (as autohydrolysis) have demonstrated to be highly effective, simple, environmentally friendly and economic. In this work, the study of the autohydrolysis of Sargassum muticum has been studied. Consequently, Simultaneous Saccharification and Fermentation took place, using different industrial strains of Saccharomyces cerevisiae and two type of experiments: i) using only the autohydrolyzed solid phase, ii) using the liquid and solid phase from the autohydrolysis procedure.info:eu-repo/semantics/publishedVersio

Formosolv pretreatment to fractionate Paulownia wood following a biorefinery approach: isolation and characterization of the lignin fraction

Paulownia is a rapid-growth tree with a high biomass production rate per year and low demand of water, which make it very suitable for intercropping systems, as it protects the crops from adverse climatic conditions, benefiting the harvest yields. Moreover, these characteristics make Paulownia a suitable raw material able to be fractionated in an integrated biorefinery scheme to obtain multiple products using a cascade conversion approach. Different delignification pretreatments of biomass have been purposed as a first stage of a lignocellulosic biorefinery. In this study, the formosolv delignification of Paulownia wood was investigated using a second order face-centered factorial design to assess the effects of the independent variables (concentrations of formic and hydrochloric acids and reaction time) on the fractionation of Paulownia wood. The maximum delignification achieved in this study (78.5%) was obtained under following conditions: 60 min, and 95% and 0.05% formic and hydrochloric acid, respectively. In addition, the remained solid phases were analyzed to determine their cellulose content and cooking liquors were also chemically analyzed and characterized. Finally, the recovered lignin by precipitation from formosolv liquor and the pristine lignin (milled wood lignin) in Paulownia wood were characterized and compared by the following techniques FTIR, NMR, high-performance size-exclusion chromatography (HPSEC) and TGA. This complete characterization allowed verifying the capacity of the formosolv process to act on the lignin, causing changes in its structure, which included both phenomena of depolymerization and condensation.This research was funded by MINECO (Spain) in the framework of the projects “Development of processes for the integral use of fast-growing biomass by means of the production of bioethanol and chemical products” with reference CTQ2012-30855 and “Multistage processes for the integral benefit of macroalgal and vegetal biomass” with reference CTM2015-68503-R, by Consellería de Cultura, Educación e Ordenación Universitaria (Xunta de Galicia) through the contract ED431C 2017/62-GRC to Competitive Reference Group BV1, and by the CITACA Strategic Partnership ED431E 2018/07, programs partially funded by European Regional Development Fund (FEDER).info:eu-repo/semantics/publishedVersio

Enhancement of the enzymatic hydrolysis of Paulownia wood using non-ionic surfactant

The abundance of lignocellulosic biomass from various industries provides a great potential feedstock for the production of value-added products. This lignocellulosic materials can be enzymatically hydrolyzed into sugars for the production of biofuels and biomaterials. However, the presence of lignin is inhibitory, becoming a major obstacle for enzymatic hydrolysis of lignocellulosic materials conducted in high solid loading. This is because the lignin acts as a protective barrier for cellulose and, thus, restricts the accessibility of the enzyme to the cellulose. Addition of surfactants, polymers, and noncatalytic proteins can improve the enzymatic hydrolysis of lignocellulosic materials by blocking the exposed lignin surfaces. In this work, the optimization of enzymatic hydrolysis of Paulownia wood was tested, evaluating the influence of: i) autohydrolysis pretreatment under non-isothermal conditions (TMAX: 210ºC, 220ºC and 230ºC), ii) solid loading (Consistency: 10, 13 and 16 %), iii) enzyme substrate ratio (ESR: 8, 12 and 16 UPF/g Paulownia), and iv) the addition of nonionic surfactant Tween 20 (0, 1.5 and 3 g/L). The enzyme employed was Cellic CTec2 (Novozymes) with an enzyme activity of 160 UFP/mL. This work suggested that autohydrolysis pretreatment could improve the enzymatic hydrolysis significantly and the addition of Tween 20 could reduce the hydrolysis time and enzyme dosage.info:eu-repo/semantics/publishedVersio

Co-valorization of discarded wood pinchips and sludge from the pulp and paper industry for production of advanced biofuels

Several lignocellulosic wastes are generated in the pulp and paper industry (PPI), such as small wood chips (pinchips) and paper sludge, presenting a high cellulose content suitable to be converted into biofuels or bio-products in a forest biorefinery scheme. In this work, two schemes of biorefinery were proposed for their valorization, processing small eucalyptus wood pinchips in two different strategies: (i) autohydrolysis at 230ºC, and (ii) autohydrolysis at 195ºC followed by organosolv process (47.7% ethanol-water, 198ºC for 60 min). More than 95% of cellulose was recovered in both schemes. In the combined process, 76% of delignification was achieved and 78% of xylan was solubilized as xylooligosaccharides. To reduce operational cost of lignocellulosic biomass-to-ethanol fermentation, the mixture of the treated eucalyptus pinchips from two processes with sludge was also proposed to increase the initial glucan content and to supply a rich source of nitrogen (present in the sludge). For that, two experimental designs were carried out for ethanol production by simultaneous saccharification and fermentation (SSF) process. Ethanol from SSF assays using sludge as co-substrate at 0.6 g of sludge/g of treated wood pinchips and 16 FPU/g of pretreated solids allowed to obtain 59 g/L (90% of conversion) and 46 g/L (96% of conversion) when blended with the wood from autohydrolysis and with the wood from autohydrolysis followed by organosolv, respectively. Overall, this study shows an alternative process valorization of biomasses derived from PPI for production of advanced biofuels and bio-products (such as xylooligosaccharides and lignin) contributing to achieving a circular economy.Xunta de Galicia | Ref. ED431C 2017/62Xunta de Galicia | Ref. ED431F 2022/09Xunta de Galicia | Ref. ED481B-2022-020Agencia Estatal de Investigación | Ref. RYC2020-030690-IUniversidade de Vigo/CISU

Feasibility of a robotic walking avatar for social pilgrimage: the first Saint James Way experience

In the field of social robotics, there is a growing interest in robotic assistants for culture and tourism, and recent advances in 5G cellular communications, radically improving end-to-end latency and throughput, are key enablers in this regard. The Saint James Way (the Way) to Santiago de Compostela, Spain, is one of the main pilgrimage routes in Christianity. Over 430,000 pilgrims traveled to Santiago in 2022. Many of them cited motivations for travel other than religion, making the Way a major European touristic attraction linking many historical landmarks in Spain. In this article, we present and describe our experience in this scenario with a robotic walking avatar that was teleoperated from Italy (2,000 km away). To the best of our knowledge, this is the first time the feasibility of such an avatar has been quantitatively assessed in terms of teleoperation performance, terrain crossing capacity, and autonomyXunta de Galicia | Ref. ED481B-2022-019Xunta de Galicia | Ref. ED481B-2022-093Xunta de Galicia | Ref. ED481B-2021-118Xunta de Galicia | Ref. ED431C 2022/04Agencia Estatal de Investigación | Ref. PID2020-116329GB-C2

Angiotensin Type 1 Receptor Antagonists Protect Against Alpha-Synuclein-Induced Neuroinflammation and Dopaminergic Neuron Death

Altres ajuts: This study received funding from the Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas' intramural program (2014/01 and 2017/02), Galician Government (Xunta de Galicia, Consellería de Educación; GRC2014/002), Navarra Government (Departamento de Salud; 046-2017), and Fondo Europeo de Desarrollo Regional (Regional European Development Fund).The loss of dopaminergic neurons and α-synuclein accumulation are major hallmarks of Parkinson's disease (PD), and it has been suggested that a major mechanism of α-synuclein toxicity is microglial activation. The lack of animal models that properly reproduce PD, and particularly the underlying synucleinopathy, has hampered the clarification of PD mechanisms and the development of effective therapies. Here, we used neurospecific adeno-associated viral vectors serotype 9 coding for either the wild-type or mutated forms of human alpha-synuclein (WT and SynA53T, respectively) under the control of a synapsin promoter to further induce a marked dopaminergic neuron loss together with an important microglial neuroinflammatory response. Overexpression of neuronal alpha-synuclein led to increased expression of angiotensin type 1 receptors and NADPH oxidase activity, together with a marked increase in the number of OX-6-positive microglial cells and expression of markers of phagocytic activity (CD68) and classical pro-inflammatory/M1 microglial phenotype markers such as inducible nitric oxide synthase, tumor necrosis factor alpha, interleukin-1β, and IL-6. Moreover, a significant decrease in the expression of markers of immunoregulatory/M2 microglial phenotype such as the enzyme arginase-1 was constantly observed. Interestingly, alpha-synuclein-induced changes in microglial phenotype markers and dopaminergic neuron death were inhibited by simultaneous treatment with the angiotensin type 1 blockers candesartan or telmisartan. Our results suggest the repurposing of candesartan and telmisartan as a neuroprotective strategy for PD