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Here, we propose an optimised protocol for controlling the initial water activity (aw) in organic reaction mixtures with soluble lipase to ensure reproducible and consistent enzyme activity measurements. Pre‐equilibration above saturated salt solutions was used to set aw of the reaction media, where aw was tracked with a hygrometer. Consistent stirring of the suspension and volume correction to compensate for solvent evaporation were found to be critical. The protocol was tested on Candida antarctica lipase B (CALB) in soluble and immobilised forms in three organic solvents (acetonitrile, methyl tert‐butyl ether, and hexane) at four different water activities ranging from 0.12 to 0.97. Soluble and immobilised CALB had similar aw‐profiles and showed the highest enzyme activity in hexane. The optimised protocol expands the possibility to study enzyme kinetics from immobilised enzymes to soluble enzymes. [ABSTRACT FROM AUTHOR]

Lipoquinones are the topic of this review and are a class of hydrophobic lipid molecules with key biological functions that are linked to their structure, properties, and location within a biological membrane. Ubiquinones, plastoquinones, and menaquinones vary regarding their quinone headgroup, isoprenoid sidechain, properties, and biological functions, including the shuttling of electrons between membrane-bound protein complexes within the electron transport chain. Lipoquinones are highly hydrophobic molecules that are soluble in organic solvents and insoluble in aqueous solution, causing obstacles in water-based assays that measure their chemical properties, enzyme activities and effects on cell growth. Little is known about the location and ultimately movement of lipoquinones in the membrane, and these properties are topics described in this review. Computational studies are particularly abundant in the recent years in this area, and there is far less experimental evidence to verify the often conflicting interpretations and conclusions that result from computational studies of very different membrane model systems. Some recent experimental studies have described using truncated lipoquinone derivatives, such as ubiquinone-2 (UQ-2) and menaquinone-2 (MK-2), to investigate their conformation, their location in the membrane, and their biological function. Truncated lipoquinone derivatives are soluble in water-based assays, and hence can serve as excellent analogs for study even though they are more mobile in the membrane than the longer chain counterparts. In this review, we will discuss the properties, location in the membrane, and syntheses of three main classes of lipoquinones including truncated derivatives. Our goal is to highlight the importance of bridging the gap between experimental and computational methods and to incorporate properties-focused considerations when proposing future studies relating to the function of lipoquinones in membranes. [ABSTRACT FROM AUTHOR]

The lack of an eco-friendly approach towards application of polyaniline as a coating material has been one of the most challenging tasks. Herein, the synthesis of green Prunus domestica gum grafted polyaniline (PDG-g-PANI) composite is reported by a cost-effective emulsion polymerization for application as an efficient anti-corrosion material for mild steel (MS) and stainless steel (SS) in a strong corroding environment. The composite formation was confirmed by Ultraviolet Visible (UV-Visible) and Fourier Transformed Infrared (FTIR) spectroscopies. X-ray diffraction data revealed the amorphous nature of the PDG-g-PANI. Scanning Electron Microscopic (SEM) images showed a bi-layered structure having a parent porous layer of PANI coated with afibrous layer of PDG. The solubility test confirmed the dissolution of PDG-g-PANI in common organic solvents such as acetone, ethanol, propanol, butanol, chloroform, N-Methyl-2-pyrrolidone, dimethyl sulfoxide, and the mixture of propanol and chloroform. The polarization curve, open circuit potential, electrochemical impendence spectroscopy (EIS), and gravimetric analysis were applied to investigate the corrosion protection behavior of the composite on MS and SS in 3.5% NaCl and 1 M H2SO4 solution. The PDG-g-PANI-coated MS exhibited 96% corrosion inhibition efficiency as compared to 86% and 43% for pristine PANI and PDG in 3.5% NaCl solution while PDG-g-PANI-coated SS showed 98% corrosion inhibition efficiency. Moreover, 99% and 96.6% corrosion protection was observed for PDG-g-PANI-coated MS and SS in 1 M H2SO4 solution. Gravimetric studies revealed that PDG-g-PANI coating can protect MS up to 93% for 14 days in salt solution while 97% corrosion inhibition efficiency was retained for 2 months in open air. [ABSTRACT FROM AUTHOR]

[Display omitted] • Toxic organic solvents were avoided in the synthesis of DHA-phospholipids (PLs). • DHA-PLs were prepared via lipase-mediated transesterification in aqueous phases. • Candida antarctica Lipase B showed 34.8% DHA incorporation and 80.0% PLs yields. • Crucial residues (S101–Y116 + V174–I210) affecting enzyme activity were confirmed. Docosahexaenoic acid-phospholipids (DHA-PLs) were prepared via lipase-mediated transesterification of DHA donor and phosphatidylcholine (PC) in a purely aqueous solution. Pre-existing carriers would play the role as "artificial interfaces" to adsorb water-insoluble PC and made them disperse in water. DHA donors were concentrated by a pH-responsive method and presented as supersaturated salt solutions. 153 triacylglycerol lipase structures were analyzed and screened in silico. Transesterification was carried out to further evaluate the six lipase candidates. Lipase B from Candida antarctica (CALB) was the best biocatalyst with 34.8% of DHA incorporation and 80.0% of PLs yields (involving 38.1% PC and 41.9% sn -1 lyso-PC). Toxic organic solvents were avoided. Six possible microunits of our aqueous system consisting of three PLs donors (PC, lyso-PC, sn -glycero-3-PC) and two DHA donors (DHA and DHA salts), were simulated by molecular dynamics (MD) to illustrate the enzymatic mechanism based on diffusional channels, competitive bindings, and enzymatic structures. [ABSTRACT FROM AUTHOR]

The cobalt carbonate hydroxide one-dimensional (1D) needle-like nanostructure is grown on the non-woven fabric via hydrothermal method. The 1D interlaced needle-like structure not only reduces the pore size of the non-woven fabric but also provides rough micro-nano structure of the superhydrophilic cobalt carbonate hydroxide/non-woven fabric, which is endowed with superhydrophobicity by coating with polydimethylsiloxane (PDMS). The resulting superwetting non-woven fabrics exhibit high separation efficiency for a series of surfactant-stabilized organic solvent/water emulsions (more than 99.3% for both W/O and O/W emulsions) and preferable recyclability (more than 10 cycles). The fluxes for all W/O and O/W emulsions are above 300 L m−2 h−1. Meanwhile the superhydrophobic fabric exhibits outstanding chemical stability in acid, alkaline and salt solution, and good mechanical durability after abrasion test with sandpaper. The comprehensive performances of the superwetting fabrics based on 1D nanostructure make them possible to be promising material for the separation of organic solvent/water mixtures in polluted water in harsh environments. [Display omitted] • The superwetting non-woven fabrics are fabricated by grafting one-dimensional (1D) needle-like nanostructure. • The 1D structure reduces the pore size of the non-woven fabric and provides rough micro-nano structure. • The resulting fabrics exhibit high separation efficiency and favorable reusability for surfactant-stabilized emulsions. • The superhydrophobic fabric possesses outstanding chemical stability and good mechanical durability. [ABSTRACT FROM AUTHOR]

Common separation materials are divided into two-dimensional (2D) materials and three-dimensional (3D) materials, among which three-dimensional materials have excellent durability and stability. Herein, we developed a durable S@P@PU sponge by simply immersing polyurethane (PU) sponges in a blending solution of starch granules and polydimethylsiloxane (PDMS). Blending starch granules and PDMS could achieve more reliable adhesion of starch granules to the PU sponge by utilizing the high adhesion of PDMS. At the same time, the presence of starch granules could make PDMS form a spot-like secondary structure on the sponge. The sponge exhibited excellent hydrophobicity and high organic solvent affinity, and could separate and absorb organic solvents from the turbulent flow. The results showed that the sponge could absorb and hold 46 times its organic solvent weight, with a separation efficiency greater than 98.5% for different organic solvents. In addition, the sponge maintained a water contact angle of more than 140° after 40 abrasion cycles or after immersion in different pH and salt solutions for 48 h, showing excellent mechanical durability and chemical stability. [Display omitted] • The modified sponge water contact angle is increased from 86° to 157°. • In extreme environments, sponges still have water contact angles of >140°. • The separation efficiency of the modified sponge is greater than 99%. • The modified sponge can hold 46 times its own weight of organic solvent. • The sponge has the advantages of low cost and short time consumption. [ABSTRACT FROM AUTHOR]

Modified antimicrobial and antifouling materials and surfaces can be used to limit the propagation of microorganisms on various surfaces and minimise the occurrence of infection, transfer, and spoilage. Increased demand for 'green' solutions for material treatment has pushed the focus towards to naturally produced antimicrobials. Tyrocidines, cyclo-decapeptides naturally produced by a soil bacterium Brevibacillus parabrevis, have a broad spectrum of activity against Gram-positive and Gram-negative bacteria, filamentous fungi, and yeasts. Continual losses in tyrocidine production highlighted the possible association of peptides to surfaces. It was found in this study that tyrocidines readily associates with many materials, with a selectivity towards polysaccharide-type materials, such as cellulose. Peptide-treated cellulose was found to remain active after exposure to a broad pH range, various temperatures, salt solutions, water washes, and organic solvents, with the sterilising activity only affected by 1% SDS and 70% acetonitrile. Furthermore, a comparison to other antimicrobial peptides showed the association between tyrocidines and cellulose to be unique in terms of antimicrobial activity. The robust association between the tyrocidines and various materials holds great promise in applications focused on preventing surface contamination and creating self-sterilising materials. [ABSTRACT FROM AUTHOR]