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This work was supported by the project “DESalgae – Capturing and re-using CO2 using deep eutectic solvents and microalgae” funded by Dutch national fund NWO Open Competition Domain Science – XS [ OCENW.XS4.162 ]; Special thanks to AlGreen B.V. (Wageningen) for providing Spirulina sp. biomass. Publisher Copyright: © 2022 The Authors. This work is the first proof-of-concept of the use of carbonic anhydrase (CA) enzyme from microalgae biomass, extracted with deep eutectic systems (DES), with the goal of engineering a solution that will lead to a breakthrough in the Carbon Capture and Utilization (CCU) strategy. Three distinct microalgae were processed-Tisochrysis lutea, Chlorella vulgaris, and Spirulina sp.-with three DES-Choline chloride-Urea (ChCl-U), Choline chloride-Poly(ethylene glycol) (ChCl-PEG), and Poly(ethylene glycol)-Urea (PEG-U). To evaluate the most promising microalgae-DES, CA activity was evaluated with a specific enzymatic activity kit and through CO2 solubility assays. Preliminary results indicate that: DES is a suitable solvent medium for CA extraction from microalgal biomass, preserving its activity (specific CA activity up to 0.70 mU.mg-1); CA extraction efficiency differs between DES and microalgal species, indicating the potential for further research; from the tested DES, the ones containing PEG were favorable to maintain CA activity (CO2 solubility up to 4 g CO2.g-1 DES). This work paves the way towards a disruptive CCU approach. publishersversion published

In this work, we propose the utilization of scCO2 to impregnate ibuprofen into the mcl-PHA matrix produced by Pseudomonas chlororaphis subs. aurantiaca (DSM 19603). The biopolymer has adhesive properties, is biocompatible and has a melting temperature of 45 °C. Several conditions, namely, pressure (15 and 20 MPa) and impregnation time (30 min, 1 h and 3 h) were tested. The highest ibuprofen content (90.8 ± 6.5 mg of ibuprofen/gPHA) was obtained at 20 MPa and 40 °C, for 1 h, with an impregnation rate of 89 mg/(g·h). The processed mcl-PHA samples suffered a plasticization, as shown by the decrease of 6.5 °C in the Tg, at 20 MPa. The polymer’s crystallinity was also affected concomitantly with the matrices’ ibuprofen content. For all the impregnation conditions tested the release of ibuprofen from the biopolymer followed a type II release profile. This study has demonstrated that the mcl-PHA produced by P. chlororaphis has a great potential for the development of novel topical drug delivery systems.

In this work, we propose the utilization of scCO2 to impregnate ibuprofen into the mcl-PHA matrix produced by Pseudomonas chlororaphis subs. aurantiaca (DSM 19603). The biopolymer has adhesive properties, is biocompatible and has a melting temperature of 45 °C. Several conditions, namely, pressure (15 and 20 MPa) and impregnation time (30 min, 1 h and 3 h) were tested. The highest ibuprofen content (90.8 ± 6.5 mg of ibuprofen/gPHA) was obtained at 20 MPa and 40 °C, for 1 h, with an impregnation rate of 89 mg/(g·h). The processed mcl-PHA samples suffered a plasticization, as shown by the decrease of 6.5 °C in the Tg, at 20 MPa. The polymer’s crystallinity was also affected concomitantly with the matrices’ ibuprofen content. For all the impregnation conditions tested the release of ibuprofen from the biopolymer followed a type II release profile. This study has demonstrated that the mcl-PHA produced by P. chlororaphis has a great potential for the development of novel topical drug delivery systems.

Lignocellulosic biomass is a renewable and sustainable feedstock, mainly composed of cellulose, hemicellulose, and lignin. Lignin, as the most abundant natural aromatic polymer occurring on Earth, has great potential to produce value-added products. However, the isolation of highly pure lignin from biomass requires the use of efficient methods during lignocellulose fractionation. Therefore, in this work, novel acidic deep eutectic solvents (DESs) were prepared, characterized and screened for lignin extraction from maritime pine wood (Pinus pinaster Ait.) sawdust. The use of cosolvents and the development of new DES were also evaluated regarding their extraction and selectivity performance. The results show that an 1 h extraction process at 175 ?C, using a novel DES composed of lactic acid, tartaric acid and choline chloride, named Lact:Tart:ChCl, in a molar ratio of 4:1:1, allows the recovery of 95 wt% of the total lignin present in pine biomass with a purity of 89 wt%. Such superior extraction of lignin with remarkable purity using a ?green? solvent system makes this process highly appealing for future large-scale applications. ? 2021 Elsevier B.V. All rights reserved. Portuguese Foundation for Science and Technology, FCTPortuguese Foundation for Science and Technology [PTDC/AGR-TEC/4814/2014, PTDC/ASPSIL/30619/2017, UIDB/05183/2020]; FCTPortuguese Foundation for Science and TechnologyEuropean Commission [SFRH/BD/132835/2017, UID/QUI/00313/2020, UIDB00102/2020]; FCT through the project COMPETE; FCT/MCTESPortuguese Foundation for Science and TechnologyEuropean Commission [UIDB/QUI/50006/2019]; ERCEuropean Research Council (ERC)European Commission [ERC-2016-COG 725034]; [CEECIND/01014/2018] ERC-2016-COG 725034 UID/QUI/00313/2020 info:eu-repo/semantics/publishedVersion

Deep Eutectic Systems (DESs) are an emerging class of green solvents with a myriad of applications, from biotechnology to material science. The high viscosity of most DESs is an obstacle that can be circumvented by the addition of water. But how much water is too much water? There is a need to understand the effect of water in the organizational dynamics of DESs, and to clarify the role of water on the physical properties of the DES, and as a functional additive. In this work, NMR spectroscopy was used to study choline chloride:glycerol (at a 1:2 molar ratio) systems with added water, at water contents ranging from 1 wt% (xw = 0.06) to 70 wt% (xw = 0.94). We identified three distinct water behaviour domains. Up to a water content of 11 wt%, water does not disrupt the DES structure; in fact, water has a glue-like effect, acting as a bridge between the DES components. Between water contents of 11 wt% and 35 wt%, the solvation of the DES components starts to occur, but the DES nanostructure is still present. At 35 wt% of water, the DES structure is disrupted, and the system transitions to a DES-in-water solution.

Recent findings have reported the reason why some living beings are able to withstand the huge thermal amplitudes between winter and summer in their natural habitats. They are able to produce metabolites decreasing deeply the crystallization temperature of water, avoiding cell disrupture due to the presence of ice crystals and overcoming osmotic effects. In vitro, the possibility to cool living cells and tissues to cryogenic temperatures in the absence of ice can be achieved through a vitrification process. Vitrification has been suggested as an alternative approach to cryopreservation and could hereafter follow an interesting biomimetic perspective. The metabolites produced by these animals are mostly sugars, organic acids, choline derivatives, or urea. When combined at a particular composition, these compounds form a new liquid phase which has been defined as Natural Deep Eutectic Solvents (NADES). In this review, we relate the findings of different areas of knowledge from evolutive biology, cryobiology, and thermodynamics and give a perspective to the potential of NADES in the development of new cryoprotective agents., The authors gratefully acknowledge the financial support of FCT through the project Des.zyme - Biocatalytic separation of enantiomers using Natural Deep Eutectic Solvents (PTDC/ BBB-EBB/1676/2014). The funding received from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement numbers REGPOT-CT2012-316331- POLARIS, as well as from European Regional Development Fund (ERDF) under the project “Novel smart and biomimetic materials for innovative regenerative medicine approaches” RL1- ABMR-NORTE-01-0124-FEDER-000016), cofinanced by North Portugal Regional Operational Programme (ON.2, O Novo Norte), under the National Strategic Reference Framework (NSRF), are also appreciatively acknowledged., info:eu-repo/semantics/publishedVersion

In this work we report a new way of producing wrinkled soft Janus spheres by using scCO 2 . The wrinkles appear in one of the half-hemispheres by the asymmetric UV irradiation of the particles followed by an anisotropic scCO 2 swelling. This treatment allows the fabrication of banded as well as sinusoidal packed wrinkles in the irradiated spheres surface. The particles were prepared from an elastomeric network consisting of two soft segments, polypropylene oxide and polybutadiene. The spheres to be treated by scCO 2 were selected taking into account the chemical composition as well as the elastic and wettability characteristics of the materials.

Enzymatic esterification is an effective route that can contribute for the separation of racemic (rac) mixtures and is thus of great importance for the pharmaceutical, food, and cosmetic industries...

Natural deep eutectic systems (NADES), which have applications as solvents for both engineering and life sci-ences, are mainly composed of sugars, aminoacids or organic acids. In this work NADES composed by glucose,urea and proline (G:U:P in a molar ratio of 1:1:1) and proline and glucose (P:G 5:3) were prepared and addedin different mass fractions to water.By differential scanning calorimetry it was verified as the crystallization tendency of water is modified even forlow fraction of NADES added. This is also observed by polarized optical microscopy which allowed followingthe formation of crystals with different crystalline morphologies as bulk water. Calorimetric data also shown asthe crystallization temperature decreases for all P:G mixtures and this shift is more accentuated for weight frac-tion of NADES higher than 0.5. Crystallization is totally suppressed for NADES fraction higher than 0.7.NADES/water mixtures cytotoxicity was evaluated in vitro, revealing that they are less toxic as compared withthe commonly used cryoprotective additives as dimethyl sulfoxide (DMSO). Additionally, cell viability testswith cell lines cryopreserved using DMSO and both the prepared NADES showed comparable viability.This work combines thermophysical data on NADES and evaluates itâ s in vitro performance, providing cues fortheir use in cryopreservation applications., European Union Horizon 2020 Program under the agreement number ERC-2016-CoG 725034 (ERC Consolidator Grant Des.solve). This research was also funded by PTDC/EQU-EQU/29851/2017. A. Paiva acknowledges the financial support from project IF/01146/2015 attributed within the 2015 FCT researcher program. This work was supported by the Associate Laboratory for Green Chemistry - LAQV which is financed by national funds from FCT/MCTES (UIDB/50006/2020 and UIDP/50006/2020)

Natural deep eutectic systems (NADES) are mostly composed of natural primary metabolites such as sugars, sugar alcohols, organic acids, amino acids and amines. These simple molecules have been identified in animals living in environments with extreme temperature amplitudes, being responsible for their survival at negative temperatures during winter. Herein, we report for the first time the use of NADES based on trehalose (Treh) and glycerol (Gly) in cryopreservation, as cryoprotective agents (CPA). The evaluation of the thermal behaviour of these eutectic systems, showed that NADES have a strong effect on the water crystallization/freezing and melting process, being able to reduce the number of ice crystals and hence ice crystal damage in cells, which is a crucial parameter for their survival, upon freezing. Using this NADES as CPA, it is possible to achieve similar or even better cellular performance when compared with the gold standard for cryopreservation dimethyl sulfoxide (DMSO). In this sense, this work relates the physical properties of the NADES with their biological performance in cryopreservation. Our comprehensive strategy results in the demonstration of NADES as a promising nontoxic green alternative to the conventional CPA's used in cryopreservation methods., The research leading to these results has received funding provided by Portuguese Foundation for Science and Technology (FCT), through project PTDC/BBB-EBB/1676/2014 – DesZyme. Funding from the European Union Horizon 2020 program has also been, granted through the project Des.solve (ERC consolidator), ERC-2016-COG 725034. J.M.S. would also like to acknowledge the financial support by the FCT through the post-doctoral grant with reference number SFRH/BPD/ 116779/2016., info:eu-repo/semantics/publishedVersion

Submitted by Maria João Antunes (mariajoao@fd.ul.pt) on 2018-02-19T16:59:42Z No. of bitstreams: 1 ulfd133828_tese.pdf: 1777637 bytes, checksum: 1290a5331c50447f48980c4f21ca99e8 (MD5) Made available in DSpace on 2018-02-19T17:00:05Z (GMT). No. of bitstreams: 1 ulfd133828_tese.pdf: 1777637 bytes, checksum: 1290a5331c50447f48980c4f21ca99e8 (MD5) Previous issue date: 2017-10-09

Supercritical carbon dioxide has been used as a green solvent due to their well-known potential in biomaterials impregnation. The versatility of this technique enables the loading of implants with Active Pharmaceutical Ingredients which present several benefits when compared with traditional techniques to impregnate active compounds. In this review, we have summarized the recent progress achieved in supercritical CO2assisted impregnation of active compounds and therapeutic deep eutectic systems for biomedical applications., 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) cofinanced 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). The authors would also like to acknowledge the financial support of the Associate Laboratory, Life and Health Sciences Research Institute / Biomaterials LA ICVS-3Bs (2015-2017). The authors would like also to thank to the financial support from the Portuguese Foundation for Science and Technology (FCT) for the fellowship grant of LAQV/BPD/037/2016, and to “Fundo Social Europeu”- FSE and “Programa Diferencial de Potencial Humano POPH”. Alexandre Barros acknowledges his FCT PhD grant SFRH/BD/97203/2013. J.M.S acknowledges the project PTDC/CTM-BIO/4706/2014 for funding via an BPD grant., info:eu-repo/semantics/publishedVersion

Some approaches have been developed in our group to investigate the role of ionic liquids as process and property modifiers of natural-based polymers. In our previous work, we proposed the use of ionic liquids as plasticizing agents for the creation of porous structures from a semi-crystalline natural-based polymer. The current work intended to complement the previous studies, evaluating the ability of ionic liquid (IL) to plasticize blends of starch with poly (lactic) acid, with different ratios of starch and PLA of 50:50 and 30:70, and its effect on supercritical fluid foaming process (SCF) and providing more insights on the mechanisms involved. For this purpose, SPLA blends were modified and processed using 1-butyl-3-methylimidazolium chloride ([bmim]Cl). Supercritical fluid foaming was studied at different soaking times (1, 3 and 6 h) using carbon dioxide at 20.0 MPa and 40 oC. The blends were characterized by different techniques, such as infra-red spectroscopy, differential scanning calorimetry and compression and tensile mechanical analysis. The morphology of the foamed structures was analyzed by scanning electron microscopy and micro-computed tomography. The results suggest that after 3h of soaking time an equilibrium state of carbon dioxide into the bulk samples is attained, yielding structures with 6% and 15% of porosity, for SPLA70 and SPLA50 respectively. The solubility of carbon dioxide withinthe matrices was studied for the same conditions and the results demonstrate a higher sorption degree in the samples doped with ionic liquid. Sorption and desorption diffusion coefficients of supercritical CO2 in the SPLA matrix were determined for the raw polymer and for the SPLA doped with [bmim]Cl. It was found that the lower desorption diffusion coefficients are related with the higher porosity obtained by the foaming process., The research leading to these results has received funding from Fundacao da Ciencia e Tecnologia (FCT) through the project ENIG-MA - PTDC/EQU-EPR/121491/2010 and from the European Union's Seventh Framework Programme (FP7/2007-2013) under Grant Agreement No. REGPOT-CT2012-316331-POLARIS. Marta Martins and Rita Craveiro are grateful for financial support from Fundacao da Ciencia e Tecnologia (FCT) through the Grants BIM/PTDC/EQUEPR/121491/2010/ENIGMA and PTDC/EQUEPR/12191/2010/ENIGMA.

Natural deep eutectic solvents (NADES) have shown to be promising sustainable media for a wide range of applications. Nonetheless, very limited data is available on the properties of these solvents. A more comprehensive body of data on NADES is required for a deeper understanding of these solvents at molecular level, which will undoubtedly foster the development of new applications. NADES based on choline chloride, organic acids, amino acids and sugars were prepared, and their density, thermal behavior, conductivity and polarity were assessed, for different NADES compositions. The NADES studied can be stable up to 170 °C, depending on their composition. The thermal characterization revealed that all the NADES are glass formers and some, after water removal, exhibit crystallinity. The morphological characterization of the crystallizable materials was performed using polarized optical microscopy which also provided evidence of homogeneity/phase separation. The conductivity of the NADES was also assessed from 0 to 40 °C. The more polar, organic acid-based NADES presented the highest conductivities. The conductivity dependence on temperature was well described by the Vogelâ Fulcherâ Tammann equation for some of the NADES studied., Fundação para a Ciência e a Tecnologia (FCT/MEC) through the grants PTDC/EQUEPR/12191/2010/ENIGMA, SFRH/BD/47088/2008 and SFRH / BPD / 44946 / 2008. We further acknowledge the financial support of FCT/MEC through the project ENIGMA — PTDC/EQU-EPR/121491/2010, and the project PEst-C/ EQB/LA0006/2013 and FCOMP-01-0124-FEDER-020646.We also acknowledge the funding from the European Union Seventh Framework Programme (FP7/2007–2013) under grant agreement no. REGPOT-CT2012-316331-POLARIS, and from the Project “Novel smart and biomimetic materials for innovative regenerative medicine approaches (Ref.: RL1 — ABMR — NORTE-01-0124-FEDER- 000016)” co-financed by the North Portugal Regional Operational Programme (ON.2 — O Novo Norte), under the National Strategic Reference Framework (NSRF), through the European Regional Development Fund (ERDF).

ETS-4 has potential applications for the size-selective adsorption and ion exchange. Iron substituted ETS-4 has been hydrothermally synthesized. The incorporation with different amount of iron has been achieved to produce Fe-ETS-4(x )( x ¼5-13), which shows the flexibility for iron substitution. Low amount of iron in precursor does not disturb the formation of ETS-4. The existence of iron was confirmed by EDS. Direct comparison between in-situ synthesized and iron exchanged samples suggested that iron in former ones does not exist in pore. The iron in the pore of ETS-4 would significantly shift the 29 Si MAS NMR resonance upfield. While in-situ synthesized Fe-ETS-4(x) samples present very similar FTIR and Raman spectra, TG and DSC curves to ETS-4, the iron exchanged ones are clear shifted. The thermal stability of in-situ synthesized Fe-ETS-4(x) samples is very similar to the parent phase, much better than that of iron exchanged one.

Deep eutectic solvents (DES) can be formed by bioactive compounds or pharmaceutical ingredients. A therapeutic DES (THEDES) based on ibuprofen, a non-steroidal anti-inflammatory drug (NSAID), and menthol was synthesized and its thermal behavior was analyzed by differential scanning calorimetry (DSC). A controlled drug delivery system was developed by impregnating a starch:poly-ϵ-caprolactone polymeric blend (SPCL 30:70) with the menthol:ibuprofen THEDES in different ratios (10 and 20 wt%), after supercritical fluid sintering at 20 MPa and 50 °C. The morphological characterization of SPCL matrices impregnated with THEDES was performed by scanning electron microscopy (SEM) and micro-computed tomography (micro-CT). Drug release studies were carried out in a phosphate buffered saline. The results obtained provide important clues for the development of carriers for the sustainable delivery of bioactive compounds., Projects ENIGMA - PTDC/EQU-EPR/121491/2010, PTDC/QUI-QUI/119210/2010, PTDC/EQU-EQU/122106/2010, PEst-C/EQB/LA0006/2013 from the European Union’s Seventh Framework Programme (FP7/2007-2013) under grant agreement n° REGPOT - CT2012-316331-POLARIS and from Project “Novel smart and biomimetic materials for innovative regenerative medicine approaches (Ref.: 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).

Natural deep eutetic solvents (NADES) are defined as a mixture of two or more solid or liquid components, which at a particular composition present a high melting point depression becoming liquids at room temperature. NADES are constituted by natural molecules and fully represent the green chemistry principles. For these reasons, the authors believe that the submit manuscript is a highly valuable contribution to the field of green chemistry and chemical engineering. For the first time, the possibility to use NADES as enhancers of supercritical fluid tecnology is revealed., The research leading to these results has received funding from Fundacao da Ciencia e Tecnologia (FCT) through the project ENIGMA-PTDC/EQU-EPR/121491/2010 and the project PEst-C/EQB/LA0006/2013. The funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement no REGPOT-CT2012-316331-POLARIS and from Project "Novel smart and biomimetic materials for innovative regenerative medicine approaches (Ref.: RL1 - ABMR - NORTE-01-0124-FEDER-000016)" cofinanced 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) and FEDER are also acknowledged. Marta Martins, Rita Craveiro and Alexandre Paiva are grateful for financial support from Fundacao da Ciencia e Tecnologia (FCT) through the grants BIM/PTDC/EQU-EPR/121491/2010/ENIGMA and SFRH/BPD/44946/2008.

Green technology is actively seeking for new solvents able to replace common organic solvents which present inherent toxicity and have a high volatility, leading to the evaporation of volatile organic compounds to the atmosphere. Over the past two decades, ionic liquids (ILs) have gained enormous attention from the scientific community and the number of reported articles in the literature has grown exponentially. Nevertheless IL “greenness” is often challenged, mainly due to their poor biodegradability, biocompatibility and sustainability. An alternative to ILs are Deep Eutectic solvents (DES). Deep eutectic solvents are defined as a mixture of two solid components, which at a particular composition present a high melting point depression becoming liquids at room temperature. When the compounds that constitute the DES are primary metabolites, namely, aminoacids, organic acids, sugars or choline derivatives, DES are so- called natural deep eutectic solvents (NADES). NADES fully represent the green chemistry principles. Can natural deep eutectic solvents be foreseen as the next generation solvents and can a similar path to ionic liquids be outlined? The current state of the art concerning the advances made on these solvents in the past few years is reviewed in this Account. More than an overview on the different applications for which they have been suggested, particularly, biocatalysis, electrochemistry, extraction new data is presented in this work. Citotoxicity of different NADES was evaluated and compared to conventional imidazolim based ionic liquids and hints on the extraction of phenolic compounds from green coffee bean and on the foaming effect of NADES are revealed. Future perspectives on the major directions towards which the research on NADES is envisaged are here discussed and these comprised undoubtedly a wide range of chemical related subjects., Alexandre Paiva, Rita Craveiro, and Marta Martins are grateful for financial support from Fundacao da Ciencia e Tecnologia (FCT) through Grants SFRH/BD/47088/2008, PTDC/EQUEPR/12191/2010/ENIGMA, and BIM/PTDC/EQUEPR/121491/2010/ENIGMA. The research leading to these results has received funding from Fundacao da Ciencia e Tecnologia (FCT) through the project ENIGMA-PTDC/EQU-EPR/121491/2010, PEst-C/EQB/LA0006/2013, from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement no REGPOT-CT2012-316331-POLARIS, and from Project "Novel smart and biomimetic materials for innovative regenerative medicine approaches (Ref.: 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) and FEDER.

In this work, blend of starch and poly-e-caprolactone (PCL) doped with different concentrations of 1-butyl-3-methylimidazolium acetate ([BMIM]Ac) or 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) was studied. The blends were characterized by mechanical analysis, infra-red spectroscopy (FTIR), differential scanning calorimetry (DSC) and dielectric relaxation spectroscopy (DRS), evaluating the IL doping effect. The samples were submitted to supercritical carbon dioxide foaming and the morphology of the structures was assessed. DSC shows a single glass transition and melting endotherm for foamed and unfoamed samples, undergoing no effect upon IL doping, and DRS shows increased molecular mobility for blends with higher IL concentrations, and some hindrance for lower ones. Conductivity for SPCL doped with 30% [BMIM]Cl, before and after foaming, is comparable to conductivity of the IL but exhibiting more stable conductivity values, opening doors for applications as self-supported conductive materials., The research leading to these results has received funding from Fundacao da Ciencia e Tecnologia (FCT) through the project ENIGMA - PTDC/EQU-EPR/121491/2010 and from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement no. REGPOT-CT2012-316331-POLARIS, PEst-C/EQB/LA0006/2013 and FEDER Marta Martins Rita Craveiro and Alexandre Paiva are grateful for financial support from Fundacao da Ciencia e Tecnologia (FCT) through the grant PTDC/EQUEPR/12191/2010/ENIGMA, BIM/PTDC/EQU-EPR/ 121491/2010/ENIGMA and SFRH/BD/47088/2008.

Deep eutectic mixtures (DES) have been proposed in the last years as viable and more sustainable solvents, in a myriad of applications. CO2 capture or adsorption is one of those possible applications, where DES can act as an alternative to the amine-based solvents that are currently being used in carbon capture and sequestration (CCS) processes. In this work, different choline chloride DES were prepared, and CO2 solubility and diffusivity coefficients were measured. The DES were immobilized in a PTFE porous support, and the pure gas permeability of 3 different gases (N2, CO2 and CH4) was assessed, as well as DES supported liquid membranes ideal selectivity. An enzyme that is able to convert CO2 into bicarbonate was also added to the DES and DES supported membranes, in order to increase the transport towards CO2. The tested DES show solubility values in line with the ones reported in literature for related DES family and ionic liquids. Solubility and diffusivity of CO2 showed the best results in the DES composed of choline chloride and urea, showing even higher values when the enzyme was dispersed. The supported liquid membranes show higher permeability towards CO2, especially in DES with choline chloride and urea. The membrane containing this DES also showed high selectivity for CO2/CH4, with values above the Robeson upper bound. This proves that DES supported membranes are a viable strategy for CO2 adsorption/sequestration and that the prepared membranes may have applications in gas separation processes, particularly in the separation of CO2 from CH4, as in the case of natural gas streams treatment or biogas.