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Abstract: BACKGROUND: This study elaborates the possibility to apply combined ionic liquid (IL) and enzyme treatments for pulp fibre modification. The approach involves swelling of fibre surfaces with IL followed by enzymatic modification of the disrupted fibre surface using carbohydrate active enzymes. RESULTS: The capacity of seven cellulose‐dissolving or cellulose‐swelling ionic liquids to swell pulp fibres was compared. In addition, thirteen cellulases and five xylanases were screened for their IL tolerance, which determines their applicability in combined or sequential IL–enzyme treatments of fibres. Among the studied ionic liquids, 1‐ethyl‐3‐methylimidazolium dimethylphosphate ([EMIM]DMP) and 1,3‐dimethylimidazolium dimethylphosphate ([DMIM]DMP) had the strongest effect on fibre swelling. These solvents were also found to be the least inactivating for the studied enzymes. CONCLUSION: Enzyme compatibility and cellulose‐dissolving capability are not two conflicting properties of an ionic liquid. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The stability of tetra-n-butylphosphonium hydroxide ([P4444][OH](aq)) solutions and their potential for wheat straw extraction are investigated. Under certain concentration ranges, aqueous [P4444][OH](aq) is known to rapidly dissolve up to 20 wt% of cellulose at 25 °C. However, at elevated temperatures and at the high concentration ranges required for cellulose dissolution, [P4444][OH](aq) irreversibly decomposes. This was determined by following the kinetics of decomposition at different temperatures and concentrations, using 31P NMR analysis of the solutions. A lower concentration range of 40 wt% [P4444][OH](aq) was observed for fractionation of wheat straw, avoiding significant decomposition of the expensive phosphonium component. Herein, the possibilities for producing cellulose-rich fractions with reduced lignin contents and hemicellulose-rich extracts are discussed. A proposal is given for a full process cycle using [P4444][OH](aq), where the phosphonium salt is used in fractionation and recovered by anion metathesis as a chloride salt. Although not demonstrated in this article, the chloride salt may be converted back to the hydroxide by means of, e.g., ion exchange. [ABSTRACT FROM AUTHOR]

• Family GH10 and GH11 xylanases tolerate superbase-derived ionic liquids differently. • Double ring in cation and larger anion lead to stronger competitive inhibition. • Enhanced hydrophobicity and polarizability of ions increase enzyme inhibition. • The optimal ionic liquids may differ for each enzyme and application process. The use of enzymes in aqueous solutions of ionic liquids (ILs) could be useful for the enzymatic treatment of lignocellulose. Hydrophilic ILs that dissolve lignocellulose are harmful to enzymes. The toleration limits and enzyme-friendly superbase IL combinations were investigated for the hyperthermophilic Thermopolyspora flexuosa GH10 xylanase (endo-1,4-β-xylanase EC 3.2.1.8) TfXYN10A and Dictyoglomus thermophilum GH11 xylanase DtXYN11B. TfXYN10A was more tolerant than DtXYN11B to acetate or propionate-based ILs. However, when the anion of the ILs was bigger (guaiacolate), GH11 xylanase showed higher tolerance to ILs. 1-Ethyl-3-methylimidazolium acetate ([EMIM]OAc), followed by 1,1,3,3-tetramethylguanidine acetate ([TMGH]OAc), were the most enzyme-friendly ILs for TfXYN10A and [TMGH]+-based ILs were tolerated best by DtXYN11B. Double-ring cations and a large size anion were associated with the strongest enzyme inhibition. Competitive inhibition appears to be a general factor in the reduction of enzyme activity. However, with guaiacolate ILs, the denaturation of proteins may also contribute to the reduction in enzyme activity. Molecular docking with IL cations and anions indicated that the binding mode and shape of the active site affect competitive inhibition, and the co-binding of cations and anions to separate active site positions caused the strongest enzyme inhibition. [ABSTRACT FROM AUTHOR]

The objective of this work was to explore the feasibility of 1,5-diazabicyclo[4.3.0]non-5-enium acetate ([DBNH][OAc]) recovery from water solution by thermal separation. The evaporation behavior of pure [DBNH][OAc] was first studied using low pressure distillation in the pressure range of 0.5–2 kPa. The dew points of the distillation products from [DBNH][OAc] were measured in the pressure range of 0.5–15 kPa and modeled using an Antoine equation. Measurements for vapor liquid equilibrium (VLE) of water + [DBNH][OAc] system were carried out using a static total pressure method. The temperature range for the VLE measurement was 303–353 K. The results showed negative deviation from the Raoult’s law. The NRTL activity coefficient model was used to correlate the VLE data. The experiments of [DBNH][OAc] product recovery from a solution containing 80 wt.% water were performed using a pilot-scale agitated thin-film evaporator. The performance of the evaporation system was analyzed as a function of the feed flow rate, the evaporator jacket temperature and the operating pressure. The analyses results indicated that the [DBNH][OAc] product with small water content (5–11.7 wt.%) was achieved by low pressure evaporation in a single stage. [ABSTRACT FROM AUTHOR]

The cell membrane is mainly composed of lipid bilayers with inserted proteins and carbohydrates. Lipid bilayers made of purified or synthetic lipids are widely used for estimating the effect of target compounds on cell membranes. However, the composition of such biomimetic membranes is much simpler than the composition of biological membranes. Interactions between compounds and simple composition biomimetic membranes might not demonstrate the effect of target compounds as precisely as membranes with compositions close to real organisms. Therefore, the aim of our study is to construct biomimetic membrane closely mimicking the state of natural membranes. Liposomes were prepared from lipids extracted from L-α-phosphatidylcholine, Escherichia coli , yeast (Saccharomyces cerevisiae) and bovine liver cells through agitation and sonication. They were immobilized onto silicon dioxide (SiO 2) sensor surfaces using N-(2-hydroxyethyl)piperazine-N′-2-ethanesulfonic acid buffer with calcium chloride. The biomimetic membranes were successfully immobilized onto the SiO 2 sensor surface and detected by nanoplasmonic sensing. The immobilized membranes were exposed to choline carboxylates. The membrane disruption effect was, as expected, more pronounced with increasing carbohydrate chain length of the carboxylates. The results correlated with the toxicity values determined using Vibrio fischeri bacteria. The yeast extracted lipid membranes had the strongest response to introduction of choline laurate while the bovine liver lipid extracted liposomes were the most sensitive towards the shorter choline carboxylates. This implies that the composition of the cell membrane plays a crucial role upon interaction with choline carboxylates, and underlines the necessity of testing membrane systems of different origin to obtain an overall image of such interactions. Unlabelled Image • Natural lipid extracts were processed into small unilamellar liposomes. • Liposomes were immobilized on the sensor surface as supported vesicle layers (SVLs). • Choline carboxylates showed different effect on SVLs from the studied extracts. • Nanoplasmonic sensing enabled fast screening of biomimetic membrane interactions. [ABSTRACT FROM AUTHOR]