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We propose an innovative approach to address the pressing need for efficient and transparent evaluation techniques to assess extraction processes' sustainability. In response to society's growing demand for natural products and the consequent surge in biomass exploration, a critical imperative arises to ensure that these processes are genuinely environmentally friendly. Extracting natural compounds has traditionally been regarded as a benign activity rooted in ancient practices. However, contemporary extraction methods can also significantly harm the environment if not carefully managed. Recognizing this, we developed a novel metric, Path2Green, tailored specifically and rooted in 12 new principles of a green extraction process. Path2Green seeks to provide a comprehensive framework beyond conventional metrics, offering a nuanced understanding of the environmental impact of extraction activities from biomass collection/production until the end of the process. By integrating factors such as resource depletion, energy consumption, waste generation, and biodiversity preservation, Path2Green aims to offer a holistic assessment of sustainability of an extraction approach. The significance of Path2Green lies in its ability to distill complex environmental data into a simple, accessible metric. This facilitates informed decision-making for stakeholders across industries, enabling them to prioritize greener extraction practices. Moreover, by setting clear benchmarks and standards, Path2Green incentivizes innovation and drives continuous improvement in sustainability efforts, being a new user-friendly methodology. [ABSTRACT FROM AUTHOR]

This study delves into an innovative biorefinery approach to extract multiple high-value compounds from a single biomass source, Halobacterium salinarum R1, a resilient halophilic microorganism. By using bio-based solvents, namely an aqueous solution of gamma-valerolactone (GVL) and ethanol, a simple and efficient pipeline approach was developed, recovering unique pigments, including C50 bacterioruberin, as well as two additional fractions consisting of protein and polysaccharides. The process is based on sustainable engineering and green chemistry principles, providing a viable alternative to replacing non-renewable solvents. The study addresses environmental concerns by employing bio-based solvents while presenting a cost-effective and sustainable solution. This approach contributes to developing a high-performance and sustainable alternative, promoting the development of a blue bioeconomy. [ABSTRACT FROM AUTHOR]

Pressurized techniques are straightforward for high-scale applications and highly controllable, which seems an excellent strategy for recovering unstable natural compounds. In this work, the main advance was the development of a platform based on the pressurized liquid extraction coupled in-line with a solid-phase extraction step (PLE-SPE) combined with the use of eutectic mixtures as solvents to promote an efficient extraction and purification of natural pigments from food wastes. Eutectic mixtures, conventionally known as (deep) eutectic solvents - (D)ES, are combinations of two or more substances with a lower melting point than any of their components. (D)ES are often referred as "green solvents" because they can potentially be more environmentally friendly than other solvents, especially volatile organic solvents (VOSs). Overall, (D)ES have the potential to contribute to the achievement of several of the SDGs (especially 3, 13, and 14) through their positive impacts on health, environment, and sustainable production and consumption practices. Thus, in this work, (D)ES were used as solvents to valorize Brazilian berry waste (Plinia cauliflora). Anthocyanins are the biomass's main compounds of commercial interest, mainly for food and cosmetic applications. However, there are several technological issues regarding color control due to their high sensitivity to light, heat, oxygen, and pH variations. Thus, the data achieved in this work highlighted the high efficiency and low environmental footprint of the PLE-SPE-(D)ES platform developed. The success of the downstream process here developed was proved by the high extraction efficiency and the purity level of the anthocyanins obtained. Besides, thermal stability analysis was evaluated, demonstrating that (D)ES are not only solvents but also stabilizing agents, improving the shelflife of the extracted colorants. [ABSTRACT FROM AUTHOR]

Marine fish industries discard huge amounts of fish waste every year, which in turn impose problems of environmental pollution and loss of economic value. About 75% of the total weight of fish is discarded in the form of skins, bones, fins, heads, guts, and scales, which contain high levels of collagen type I. Generally, major sources for commercial collagens are the skin and bone of pigs and cows; however, these sources are chiefly associated with the risk of transference of zoonotic diseases or religious issues. Traditional protocols applied to the extraction of collagen are outdated, mainly with respect to present demands to develop more sustainable processes. This work explores the use of sustainable solvents, such as deep eutectic solvents (DES), to develop a more efficient, cost-effective and biocompatible process to extract collagen from waste from the fish industry waste. The extraction of collagen from the skin of Atlantic cod (Gadus morhua) using aqueous solutions of various eutectic solvents was studied, and after selection of the best solvent, an aqueous solution of urea (U) and lactic acid (LA) at a molar ratio of 1 : 2 (U : LA 1 : 2), the collagen extracted was properly characterized using SDS-PAGE, CD, FTIR, and XRD, and shown to be of type I. The results obtained here demonstrate an improvement in the yield and quality of the extracted collagen when eutectic mixtures were applied instead of acetic acid. After optimization of the process conditions, a maximum extraction yield of 6% was obtained for the aqueous solution of U : LA 1 : 2 at 0.75 M. The present work demonstrates the potential use of codfish skin waste and an aqueous solution of a DES to develop a more environmentally-friendly process to obtain high-quality collagen type I. It is an effort to convince industries to valorize their own residues under the guidelines of a circular economy. [ABSTRACT FROM AUTHOR]

Zwitterionic compounds (ZIs) have been attracting much attention due to their properties. Unlike ionic liquids – constituted by separated ions – the ZI structures with their cations and anions covalently bonded exhibit added complexity and diversity, suggesting that their ecotoxicological behavior should probably not be extrapolated from those of ionic liquids. This study addresses the aquatic toxicity of ZIs towards the bacterium Allivibrio fischeri and the microalga Raphidocelis subcapitata. Sixteen ZIs comprising five different cationic groups (ammonium, imidazolium, pyridinium, pyrrolidinium and piperidinium) and two anionic groups (sulfonate and carboxylate) were studied, and the relationships between their structure and toxicity are reported. All studied ZIs are harmless or practically harmless for both microalga and bacterium (median effective concentration, EC50 >100 mg L−1), presenting a significantly lower hazardous potential to aquatic species than their ionic liquid counterparts. The results also show that the increased hydrophobicity of ZIs, owing to the increase of the cation alkyl chain or the spacer length, has a significant influence on EC50 values for microalga, which in turn causes higher toxicity. However, no significant differences were observed when considering the various cationic groups of the ZIs studied, unlike what is known for ecotoxicity of the ionic liquids. Also, no relationships were found between the chemical structure of ZIs and EC50 values determined for the bacterium A. fischeri. The structural differences between ZIs and ionic liquids result in different mechanisms of interactions with microalgae and bacteria membranes, which may explain why the ecotoxicity heuristic rules previously reported for ionic liquids do not seem to apply to ZIs. [ABSTRACT FROM AUTHOR]

The toxicity of Ionic Liquids (ILs) to aquatic organisms has been a matter of substantial interest, involving the toxicity assessment for a small number of species, which is limitative given the variation in species sensitivity to different classes of ILs. Therefore, the main objective of this study was to validate, using an integrative approach (i.e., integrating the responses of several species), the heuristic rules that have been assumed for the ecotoxicity of ILs, namely the effects of the cation, elongation of the cation alkyl chain and anion moiety. For this purpose, four ILs were selected as models and their toxicity was determined for a wide variety of species, which allowed the development of species sensitivity distribution curves. The analysis of the distribution curves enables the determination of hazard concentrations affecting 5% of the represented communities (HC5) and also the establishment of structure–ecotoxicity relationships for ILs. The median effect concentration (EC50) values varied widely and the species most sensitive to each IL was variable. The integrative HC5 values varied by five orders of magnitude, between 3.020 × 10−3 mg L−1 representing the 1-dodecyl-3-metilimidazolium chloride, which raises concerns on the environmental hazardous potential of this IL, and 106.9 mg L−1 for cholinium chloride, which confirms its low environmental toxicity. The SSD approach showed cholinium chloride as the least toxic IL, followed by cholinium dihydrogenocitrate, 1-ethyl-3-methylimidazolium and 1-dodecyl-3-methylimidazolium chloride, as the most toxic. This illustrates the minor effect of the anion on toxicity for this set of ILs, whereas the cation and the cation alkyl chain length had pronounced effects, validating the heuristic rules defining structure–ecotoxicity relationships of ILs. A very strong linear correlation between hydrophobicity and HC5 was found (ρ = −0.9991). This approach allows a more efficient prediction of the potential environmental effects of ILs, thus preventing the need to comprehensively assess to the ecotoxicity of all ILs, which can be many within each family and each cation/anion possible combination. Ultimately, this will sustain the development of ILs posing less environmental hazards nonetheless retaining the desired performance. [ABSTRACT FROM AUTHOR]

Luminescent solar concentrators (LSCs) are a solution to overcome the mismatch between solar cell absorption and the solar spectrum, facilitating the integration of photovoltaic (PV) devices into the urban environment, since they can be incorporated in building façades and windows. Challenges include the search for environmentally friendly materials with chemical and optical stabilities. The enhanced green fluorescent protein (eGFP) was efficiently applied as an optically active center. eGFP absorbs in the UV/visible range and converts it into green emission with a maximum absolute quantum yield of ∼0.50. Here, we report the use of eGFP to fabricate planar LSCs in the liquid (aqueous solution) and solid state (incorporated in organic–inorganic hybrids), which were coupled to commercial Si-based PV cells yielding power conversion efficiency values of up to ∼0.35%. These results are higher than the figures of merit for naturally-based fluorescent proteins in aqueous media, with the advantage of presenting enhanced photostability when stored under ambient conditions. These are relevant features, uncommon in organic-based materials, which significantly contribute to the potential of naturally-based molecules in the development of LSCs as reliable, sustainable and competitive energy systems. [ABSTRACT FROM AUTHOR]

Separation and purification of biomacromolecules either in biopharmaceuticals and fine chemicals manufacturing, or in diagnostics and biological characterization, can substantially benefit from application of microfluidic devices. Small volumes of equipment, very efficient mass and heat transfer together with high process control result in process intensification, high throughputs, low energy consumption and reduced waste production as compared to conventional processing. This review highlights microfluidics-based separation and purification of proteins and nucleic acids with the focus on liquid–liquid extractions, particularly with biocompatible aqueous two-phase systems, which represent a cost-effective and green alternative. A variety of microflow set-ups are shown to enable sustainable and efficient isolation of target biomolecules both for preparative, as well as for analytical purposes. [ABSTRACT FROM AUTHOR]

A downstream process combining PEGylation reaction and the use of enzyme conjugates acting as phase-forming components of aqueous biphasic systems (ABS) is proposed here. In this approach, citrate buffer (pH = 7.0) was used simultaneously to stop the reaction (avoiding the use of hydroxylamine) and as a phase forming agent inducing the phase separation of the PEGylated proteins. The partition of the bioconjugates was assessed using two model enzymes of small size [cytochrome c (Cyt-c) and lysozyme (LYS)], and two of large size [ L -asparaginase (ASNase) and catalase (CAT)] as well as reactive PEG of 5, 10, 20 and 40 kDa. The effect of the reaction time on the PEGylation and recovery steps was also evaluated. All reactive PEGs allowed high selectivity in the separation of PEGylated proteins from native proteins (S > 100). A positive effect in terms of selectivity was found for longer reaction times. It allowed greater amounts of PEGylated proteins, with an increase of the PEG-protein rich-phase volume (top phase), allowing 100% of recovery of PEGylated proteins. More selective systems were obtained for Cyt-c and LYS (S > 100) compared to those for ASNase and CAT (40 < S < 60); nevertheless for all, the native and PEGylated proteins had their biological activity preserved. Envisioning the industrial potential evaluation, an integrated process diagram was defined combining the PEGylation reaction with the purification of the protein conjugates. Two different scenarios were investigated considering the PEGylation reaction performance. For both approaches (complete and incomplete PEGylation reaction), high recovery yields and purities were achieved for the PEGylated conjugates (92.1 ± 0.4% < %RecTCyt-c-PEG < 98.1 ± 0.1%; 84.6% < purity < 100%) and for the unreacted enzyme (%RecBCyt-c = 81 ± 1%; purity = 97.7%), while maintaining their structural integrity. [ABSTRACT FROM AUTHOR]

Herein, the effective use of aqueous biphasic systems (ABS) in Fast Centrifugal Partition Chromatography (FCPC) for the purification of PEGylated cytochrome c conjugates is shown. High recoveries (between 88% and 100%) and purities (∼100%) were obtained. Both the unreacted cytochrome c and solvents may be recovered and reused, thus allowing the design of a sustainable process in a continuous regime for the isolation of bioconjugates. This process allowed the reduction of the complete E-factor and carbon footprint at circa 100% and 67%, respectively, reinforcing the important environmental contribution of recycling units. [ABSTRACT FROM AUTHOR]

A tuneable thermoresponsive system based on combinations of sodium dodecyl sulfate surfactant with tetrabutylammonium chloride salt is presented as an integrated process for the solid–liquid extraction of violacein from bio-engineered Yarrowia lipolytica yeast and its purification by cloud-point separation from contaminant proteins. [ABSTRACT FROM AUTHOR]

Cytochrome-c from equine heart was kinetically and thermodynamically investigated either in its native (Cyt-c) or PEGylated forms with different PEGylation degrees (Cyt-c–PEG-4 and Cyt-c–PEG-8). Maximum activities were observed at 80 °C, and the irreversible deactivation was well described by first-order kinetics. The results of activity at different temperatures were used to estimate the activation energy of the catalysed Cyt-c reaction (E* = 10.22 ± 0.40, 7.51 ± 0.06 and 8.87 ± 0.29 kJ mol−1 for Cyt-c, Cyt-c–PEG-4 and Cyt-c–PEG-8) and the standard enthalpy variation of enzyme unfolding (UGRAPHIC DISPLAY="INLINE" ID="UGT1" SRC="UGT1"/ = 33.82 ± 4.92, 109.4 ± 13.1 and 58.43 ± 3.11 kJ mol−1 for Cyt-c, Cyt-c–PEG-4 and Cyt-c–PEG-8, respectively). The results of residual activity tests allowed estimating the activation energy (Ed* = 50.51 ± 1.71, 72.63 ± 0.89 and 63.36 ± 1.66 kJ mol−1 for Cyt-c, Cyt-c–PEG-4 and Cyt-c–PEG-8), enthalpy (ΔH‡), entropy (ΔS‡) and Gibbs free energy (ΔG‡) of the enzyme irreversible denaturation. The higher enthalpic contributions of PEGylated conjugates and the increase in ΔG‡, compared to the native protein, indorsed the protective role of PEGylation. Negative values of ΔS‡ suggested the occurrence of an aggregation phenomenon by increasing the temperature, which was confirmed by circular dichroism. The estimated thermodynamic parameters suggest that PEGylated Cyt-c forms have enhanced thermostability, which would be of great significance for industrial biosensing applications. [ABSTRACT FROM AUTHOR]

R-phycoerythrin is a high added-value protein found in red macroalgae with several interesting properties. Despite the promising results found when R-phycoerythrin is used as an optically active center in luminescent solar concentrators (LSCs), it still has some problems that can be attributed to the low stability of the R-phycoerythrin in the presence of the specific contaminant proteins found in the crude extract. The development of downstream strategies able to reduce the use of environmentally hazardous solvents, while improving the purification without compromising the R-phycoerythrin structural integrity is still the biggest challenge to overcome. Aqueous micellar two-phase systems (AMTPS) appear as an appealing fractionation approach since they allow the processing of systems with larger water contents, while displaying great selectivity and biocompatibility with several biomolecules. Moroever, AMTPS that mix surfactants and surface-active ionic liquids are shown to significantly enhance protein purification. In this work, mixed AMTPS were applied to the R-phycoerythrin purification from red macroalgae. After the process optimization, this work proposes the application of two consecutive steps of purification as the final process to isolate R-phycoerythrin from the remaining proteins composing the crude extract, while maintaining the structural integrity of R-phycoerythrin, as requested to be used in the LSC. Besides a good performance, the two-step approach developed was also shown to have a lower environmental impact with a carbon footprint decrease of 16%, when compared with the conventional AMTPS. [ABSTRACT FROM AUTHOR]

Nowadays, one of the biggest challenges for society is the development of appropriate technologies to process the waste residue produced worldwide. In the food sector, the generated waste is estimated to be nearly billions of tons annually. Brazil is one of the most representative examples of the economic and industrial potential of underexplored residues and raw materials. The palm heart, scientifically known as Bactris gasipaes, mainly its fruits, is one of the many examples found in Brazilian flora. The fruits have significant amounts of carotenoids, namely, the all-trans-β-carotene, all-trans-lycopene and the rare all-trans-γ-carotene, which are considered as excellent raw materials of commercial interest. However, the main challenge that remains is their efficient recovery. This work proposes the development of a performant process of extraction mediated by the use of ionic liquid (IL)-based ethanolic solutions. Four ILs were examined, as well as the solid–liquid ratio R(S/L), number of extractions, the time of extraction, the co-solvent-ratio R(IL/E) and the homogenization method employed. After selecting the best solvent ([C4mim][BF4]) and process conditions (extraction yield of 172 ± 18 μgcarotenoids gdried biomass−1), the IL-ethanolic solution recyclability was tested by freezing/precipitating the IL (maximum of 94% of IL recovered), proving its success for at least 10 cycles while decreasing the process carbon footprint by 50% compared with the conventional method using acetone. [ABSTRACT FROM AUTHOR]

Cell membrane models have been used to evaluate the interactions of various imidazolium-based ionic liquids (ILs) with Langmuir monolayers of two types of phospholipids and cholesterol. Data from surface pressure isotherms, Brewster angle microscopy (BAM) and polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS) pointed to significant effects on the monolayers of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and cholesterol, used to mimic the membranes of eukaryotic cells, for ILs containing more than 6 carbon atoms in the alkyl chain (i.e. n ＞ 6). For ILs with less hydrophobic tails (n≤ 6) and low concentrations, the effects were almost negligible, therefore, such ILs should not be toxic to eukaryotic cells. The hydrophobicity of the anion was also proved to be relevant, with larger impact from ILs containing tetrafluoroborate ([BF4]−) than chloride (Cl−). Molecular dynamics simulations for DPPC monolayers at the surface of aqueous solutions of alkylimidazolium chloride ([Cnmim]Cl) confirm the penetration of the IL cations with longer alkyl chains into the phospholid monolayer and provide information on their location and orientation within the monolayer. For monolayers of dipalmitoylphosphatidyl glycerol (DPPG), which is negatively charged like bacteria cell membranes, the ILs induced much larger effects. Similarly to the results for DPPC and cholesterol, effects increased with the number of carbon atoms in the alkyl chain and with a more hydrophobic anion [BF4]−. Overall, the approach used can provide relevant information of molecular-level interactions behind the toxicity mechanisms and support the design of (quantitative) structure–activity relationship models, which may help design more efficient and environmentally friendly ILs. [ABSTRACT FROM AUTHOR]

Phenolic compounds are ubiquitous biomolecules exhibiting a wide range of physiological properties, with application in the pharmaceutical and nutraceutical fields. In this work, aqueous biphasic systems (ABS) formed by polyethylene glycol and sodium polyacrylate, and inorganic salts or ionic liquids as electrolytes, were applied for the purification of caffeic, ferulic and protocatechuic acids (CA, FA, and PA, respectively), vanillin (VN) and syringaldehyde (SA), followed by the use of centrifugal partition chromatography (CPC) to reinforce the fractionation process scale-up. In single-step experiments in ABS, high selectivities and adequate partition coefficients (KCA = 2.78 ± 0.20; KPA = 0.44 ± 0.04; KFA = 0.23 ± 0.01; KVN = 1.12 ± 0.05 and KSA = 1.23 ± 0.02) were achieved using ABS formed by sodium chloride as the electrolyte. This system was further applied in CPC, allowing an efficient separation of the five phenolic compounds after the optimization of the equipment operational conditions, while demonstrating the potential of polymer-based ABS to be used in liquid–liquid chromatography. Finally, the recovery of the phenolic compounds (between 65 and 87%) with high purity from the ABS phases was demonstrated, allowing the reuse of the ABS phase-forming components, which was proved to be of low environmental impact. In fact, in a scenario where the polymeric phases are reused, the carbon footprint is decreased to 36%, as the consumption of new chemicals and water reduces considerably. [ABSTRACT FROM AUTHOR]

Chemical PEGylation of proteins has been used to improve their physicochemical properties and kinetics. However, the PEGylation reactions lead to a heterogeneous mixture of PEGylated conjugates and unreacted protein, which is a challenge for the design of an efficient downstream process. The purification of PEGylated proteins should address the two main issues: the separation of PEGylated conjugates from the unreacted protein and the fractionation of the PEGylated conjugates on the basis of their degree of PEGylation. The present study aims at the development of liquid–liquid extraction processes for the purification of PEGylated conjugates. An initial study of the partition behavior of cytochrome c and their PEGylated conjugates (Cyt-c-PEG-4 and Cyt-c-PEG-8) on polyethylene-glycol (PEG) + potassium phosphate buffer (pH = 7) aqueous biphasic systems (ABS) shows that PEGs with intermediate molecular weights (PEG MW = 1000–2000) allow the separation of the PEGylated conjugates from the unreacted protein in a single step. It is further shown that the PEGylated conjugates can be efficiently separated using ABS based on PEGs with high molecular weight (PEG MW = 6000–8000) and a study of the protein stability after purification was carried using circular dichroism. A downstream process to separate Cyt-c, Cyt-c-PEG-4 and Cyt-c-PEG-8 with high purities (96.5% Cyt-c, 85.8% Cyt-c-PEG-4, and 99.0% Cyt-c-PEG-8) was developed. The process proposed addresses not only the efficient separation of each of the protein forms but also the recycling of the unreacted protein purified and the ABS phases, which was successfully used in a new step of PEGylation. [ABSTRACT FROM AUTHOR]

Herein we propose an alternative way to distinguish ionic liquids from Coulombic-dominated salts, based not on their upper limit melting temperature (100 °C), but on the trend of their phase-forming abilities to create aqueous biphasic systems as a function of temperature, in which a wider plethora of interactions can be appraised. [ABSTRACT FROM AUTHOR]

Lignin-based materials and chemicals represent a large class of potential added-value compounds for biorefineries; however, the difficulty in fractionating heterogenous phenolic compounds that result from lignin depolymerisation still remains a challenge. Herein, a set of polymer-based aqueous biphasic systems (ABS) comprising sodium polyacrylate (NaPA 8000) and polyethylene glycol (PEG 8000), in which ionic surfactants and ionic liquids are used as electrolytes at concentrations below 1 wt%, is investigated for this purpose. Binodal curves were determined for three electrolyte concentrations, namely, 0.01, 0.1 and 1.0 wt%, and an intermediate electrolyte concentration was selected to investigate the partition of five phenolic compounds, caffeic acid, vanillic acid, gallic acid, vanillin and syringaldehyde, on these systems. The results show that the ABS allow the manipulation of the partition of the five phenolic compounds, which culminates with their selective isolation, with vanillin selectivities of SVN/VA = 23.75, SVN/GA = 12.52 and SVN/CA = 8.47. The electrolyte nature seems to play an important role in the fractionation of the phenolic compounds, due to the difference in their hydrophobic nature and speciation. This study demonstrates the ability of polymeric-based ABS, using ionic surfactants or ionic liquids as electrolytes, to efficiently separate and isolate five structurally similar phenolic compounds using a low-cost and very eco-friendly integrated process. [ABSTRACT FROM AUTHOR]

Furans and their derivatives are well-known chemical building blocks common in plant biomass, and are abundantly used in food, medicines and industrial processes. As a bio-renewable resource, obtainable from the abundant and inexpensive lignocellulosic biomass, there is a growing interest in their study, physico-chemical characterization and application. Due to their biological origin, there is a presumption of low toxicity and high biodegradability for these compounds, which makes them “green” solvents, and thus potential substitutes of the classical organic solvents or oil derived commodities. Surprisingly, their ecotoxicity is poorly characterized. The few studies dealing with the toxicity of furans, namely towards animals, have presented contradictory results. In this work, the toxicity of eighteen furans and their derivatives was evaluated by the Microtox toxicity assay, using the marine bacterium Vibrio fischeri. Different levels of toxicity were observed among the furan derivatives investigated. The results obtained suggest that it might not be adequate to consider furans and their derivatives as “green” solvents as, in general, furans are more toxic than the classical solvents. Nevertheless, more data and studies across more trophic levels are necessary to fully understand the effects of furans on the environment as well as their biodegradability. [ABSTRACT FROM AUTHOR]

Bioactive compounds extracted from natural renewable sources have attracted increased interest from both industry and academia. Several biocompounds are present in red macroalgae, among which R-phycoerythrin (R-PE), which is a phycobiliprotein with a wide range of applications. The major drawback associated with it is the absence of an efficient, low cost and green extraction and purification methodology capable of recovering phycobiliproteins (and, in particular, R-phycoerythrin) from the biomass, while maintaining their structure and activity. The search for novel and higher performance extraction processes is thus of extreme relevance. In this work, aqueous solutions of ionic liquids were screened for the extraction of phycobiliproteins from Gracilaria sp. The most promising solvents were identified and operational conditions such as extraction time, solid–liquid ratio, solvent concentration and pH were optimized aiming to develop a new and more efficient approach to extract phycobiliproteins. The efficiency of the proposed process is demonstrated with aqueous solutions of cholinium chloride, since the extraction of phycobiliproteins was increased to 46.5% when compared with the conventional methodology, while the protein secondary structure and the chromophore conformation integrity are maintained. [ABSTRACT FROM AUTHOR]

This work aims at developing a process to valorise pharmaceutical wastes through the recovery of pharmaceutically active compounds. The ibuprofen extraction and isolation from solid pharmaceutical wastes is used here as a case study and an integrated approach comprising the ibuprofen solid–liquid extraction, the removal of the insoluble excipients present in the pills, the target drug recovery and the recycling of the aqueous solutions is proposed. The present work is centred on the optimization of the first (solid–liquid extraction) and third (drug recovery) steps mentioned above. For the solid–liquid extraction step, various ionic liquid aqueous solutions were tested, tetrabutylammonium chloride ([N4444]Cl) being adopted to further optimize the process. A solution composed of 45 wt% of [N4444]Cl + 5 wt% of citrate buffer + 50 wt% of H2O led to the highest ibuprofen extraction efficiency (EEIBU = 97.92 ± 2.65%) while in the absence of citrate the extraction efficiency was somewhat lower (EEIBU = 93.53 ± 0.62%). The polishing task was affected by the type of aqueous solution utilized during the solid–liquid extraction step: in the presence of citrate buffer water was not prone to induce significant ibuprofen precipitation (maximum REIBU of 34.71 ± 4.00%) the aqueous KCl solution being the best option (maximum REIBU of 87.97 ± 1.00%); when no citrate buffer is used water can be used as an anti-solvent with a maximum REIBU of 91.60 ± 0.19% while aqueous KCl solutions lead to an REIBU up to 97.07 ± 0.14%. Based on these results an integrated process is proposed for the ibuprofen recovery and isolation aimed at adding value to pharmaceutical wastes. [ABSTRACT FROM AUTHOR]

This study is aimed at developing a sustainable process for the recovery of valuable drugs from pharmaceutical wastes using ionic liquid (IL)-based aqueous biphasic systems (ABS). Because in pharmaceutical wastes, excipients represent the major contaminants, the search for selective routes for their elimination is of primordial relevance and for that purpose IL-based ABS were evaluated. The effects of different process parameters, namely the IL nature, pH and mixture composition used in the extraction system, were studied and the process was optimized to maximize the extraction of the antidepressant from pharmaceutical wastes. Moreover, the maximum amount of amitriptyline able to be processed using such systems was assessed. The set of ABS investigated herein revealed a high extraction performance, as indicated by the outstanding logarithmic functions of the amitriptilyne partition coefficients ranging from 2.41 ± 0.05 to ＞2.5 and extraction efficiencies between 66% ± 1% and 100%. The best ABS and conditions were considered in the development of an integrated multi-step purification process. The process here proposed comprises three main stages as follows: the solid–liquid extraction of the antidepressant from ADT 25 pills, its purification using the optimal IL-based ABS and the antidepressant isolation by precipitation with anti-solvent. After the removal of most water insoluble excipients in the first step, with the selected IL-based ABS, it was possible to further eliminate water soluble contaminants. A high capability of extraction and purification, leading to the selective separation of amitriptyline hydrochloride from the main contaminants contained in solid pharmaceutical wastes was achieved. Finally, the isolation of the amitriptilyne in a pure state was successfully accomplished through precipitation with the anti-solvent. [ABSTRACT FROM AUTHOR]

Aqueous two-phase systems (ATPS) are efficient, environmentally friendly, and “biocompatible” separation processes, which allow the recovery of enzymes. The most common systems are based on polymers and salts, and recently, to overcome the low polarity difference between the phases of the polymeric systems, ATPS based on ionic liquids (ILs) were proposed and have been successfully applied in this field. This work discusses the use of imidazolium-based ILs not as phase forming compounds but as adjuvants (5 wt%) in ATPS of polyethylene glycol systems (1500, 4000, 6000 and 8000 g mol−1) with potassium phosphate buffer at pH 7, in the extraction and purification of a lipase produced by submerged fermentation by Bacillus sp. ITP-001. An initial optimization study was carried out with the commercial lipase B from Candida antarctica (CaLB) allowing us to further purify the commercial CaLB (purification factor = 5.2). Using the optimized conditions, a purification factor of 245 for the lipase from Bacillus sp. ITP-001 was achieved with 1-hexyl-3-methyl imidazolium chloride. The high purification factor is a consequence of the favorable interactions between the IL and the contaminant proteins that migrate for the PEG-rich phase, where the IL also concentrates preferentially, while the enzyme remains in the salt-rich phase. [ABSTRACT FROM AUTHOR]

The design of ionic liquids has been focused on the cation–anion combinations but other more subtle approaches can be used. In this work the effect of the branching of the cation alkyl chain on the design of ionic liquids (ILs) is evaluated. The mutual solubilities with water and toxicities of a series of bis(trifluoromethylsulfonyl)-based ILs, combined with imidazolium, pyridinium, pyrrolidinium, and piperidinium cations with linear or branched alkyl chains, are reported. The mutual solubility measurements were carried out in the temperature range from (288.15 to 323.15) K. From the obtained experimental data, the thermodynamic properties of the solution (in the water-rich phase) were determined and discussed. The COnductor like Screening MOdel for Real Solvents (COSMO-RS) was used to predict the liquid–liquid equilibrium. Furthermore, molecular dynamic simulations were also carried out aiming to get a deeper understanding of these fluids at the molecular level. The results show that the increase in the number of atoms at the cation ring (from five to six) leads to a decrease in the mutual solubilities with water while increasing their toxicity, and as expected from the well-established relationship between toxicities and hydrophobicities of ILs. The branching of the alkyl chain was observed to decrease the water solubility in ILs, while increasing the ILs solubility in water. The inability of COSMO-RS to correctly predict the effect of branching alkyl chains toward water solubility on them was confirmed using molecular dynamic simulations to be due to the formation of nano-segregated structures of the ILs that are not taken into account by the COSMO-RS model. In addition, the impact of branched alkyl chains on the toxicity is shown to be not trivial and to depend on the aromatic nature of the ILs. [ABSTRACT FROM AUTHOR]

This work reports a promising approach to the development of novel self-buffering and biocompatible ionic liquids for biological research in which the anions are derived from biological buffers (Good's buffers, GB). Five Good's buffers (Tricine, TES, CHES, HEPES, and MES) were neutralized with four suitable hydroxide bases (1-ethyl-3-methylimidazolium, tetramethylammonium, tetraethylammonium, and tetrabutylammonium) producing 20 Good's buffer ionic liquids (GB-ILs). The presence of the buffering action of the synthesized GB-ILs was ascertained by measuring their pH-profiles in water. Moreover, a series of mixed GB-ILs with wide buffering ranges were formulated as universal buffers. The impact of GB-ILs on bovine serum albumin (BSA), here used as a model protein, is discussed and compared with more conventional ILs using spectroscopic techniques, such as infrared and dynamic light scattering. They appear to display, in general, a greater stabilizing effect on the protein secondary structure than conventional ILs. A molecular docking study was also carried out to investigate on the binding sites of GB-IL ions to BSA. We further used the QSAR-human serum albumin binding model, log K(HSA), to calculate the binding affinity of some conventional ILs/GB-ILs to HSA. The toxicity of the GB and GB-ILs was additionally evaluated revealing that they are non-toxic against Vitro fischeri. Finally, the GB-ILs were also shown to be able to form aqueous biphasic systems when combined with aqueous solutions of inorganic or organic salts, and we tested their extraction capability for BSA. These systems were able to extract BSA with an outstanding extraction efficiency of 100% in a single step for the GB-IL-rich phase, and, as a result, the use of GB-IL-based ABS for the separation and extraction of other added-value biomolecules is highly encouraging and worthy of further investigation. [ABSTRACT FROM AUTHOR]

The activity of the commercial enzyme Candida antarctica lipase B (CaLB), in aqueous solutions of the ionic liquid 1-decyl-3-methylimidazolium chloride, [C10mim]Cl, at pH 7.0 was investigated. The relative enzyme activity (ActIL/ActBf) for ionic liquid molar concentrations ranging from 0.000–0.150 mol L−1 show an increase up to six fold in ActIL/ActBf, with the ionic liquid molar concentration. This phenomenon is shown to be related with the formation of micelles originated by the self-aggregation of [C10mim]Cl. The enzyme activation energy is not affected by the ionic liquid presence, suggesting the absence of structural changes in the enzyme induced by the ionic liquid. It is here demonstrated, for the first time, that it is possible to significantly increase the activity of an enzyme simply by using aqueous solutions of ionic liquids. [ABSTRACT FROM AUTHOR]

Phenolic acids are ubiquitous biomolecules exhibiting a wide range of physiological properties, with application in the pharmaceutical and nutraceutical fields. In this work, aqueous biphasic systems (ABS) formed by polyethylene glycol and sodium polyacrylate, and inorganic salts or ionic liquids as electrolytes, were applied to the purification of caffeic, ferulic and protocatechuic acids, followed by the use of centrifugal partition chromatography (CPC) to reinforce the fractionation process scale-up. In single-step experiments in ABS, high selectivities (S FA/CA = 12.09; S CA/PA = 6.32; S FA/PA = 1.91) and adequate partition coefficients (K CA = 2.78 ± 0.20; K PA = 0.44 ± 0.04; K FA = 0.23 ± 0.01) were achieved using ABS formed by sodium chloride as electrolyte. This system was further applied in CPC, allowing an efficient separation of the three phenolic acids after the optimization of the equipment operational conditions, while demonstrating the potential of polymer-based ABS to be used in liquid-liquid chromatography. Finally, the recovery of the phenolic acids (≥ 65%) with high purity from the ABS phases was demonstrated, followed by the reuse of the phase-forming components.