A robust surface with superhydrophobicity and underwater superoleophobicity for on-demand oil/water separation

Superhydrophobic and underwater superoleophobic surface combines superiorities of the two opposite wettabilities. Generally, such surface is constructed by hydrophilic areas and hydrophobic areas treated by fluorine-containing modifiers. However, the surface...

Production and Application of Biosurfactants in Biotechnology

Biosurfactants possess both hydrophilic and hydrophobic areas and are generated on the microbial membrane or excreted over the outer membrane. Amphipathicity leads to reduce strength and interfacial tension between the individual molecules on the surface and the two-state immiscible sector. Regarding the low critical micelle concentration (CMC) and high surface activity, biosurfactants can be effective alternatives to their synthetic equal one. Plant-based oils and fats are used in biosurfactants production. Many wastes are produced by the oil and grease industries, tallow, residual oils, marine oils, soapstock, burnt oils, and Manipura. The operation of industrial fatty acid excesses is promising for expansion and transformation. Via making various substances like olive oil mill, acid, whey, and molasses, the agro-industry can ease biosurfactant creation. Biosurfactants have many advantages over chemical production, involving capable of decomposition higher by bacteria or living organisms, less poison, environmental concordance, higher foaming, and the rate of its selection is higher. They can also adjust to the highest salinity, pH, and temperatures and can be produced out of renewable materials, resulting in an increased demand for biosurfactants. Bioemulsifiers and biosurfactants (BSs) have various applications and are a considerable character in many industrial fields, as well as biotechnological features, including pollutant biodegradation, microbial enhanced oil recovery (MEOR), and pharmaceutics. This review the latest information and improvement in biosurfactant application and development for more output and future applicability.

Invasion of Epithelial Cells Is Correlated with Secretion of Biosurfactant via the Type 3 Secretion System (T3SS) of Shigella flexneri

Biosurfactants are amphipathic molecules produced by many microorganisms, usually bacteria, fungi, and yeasts. They possess the property of reducing the tension of the membrane interfaces. No studies have been conducted on Shigella species showing the role of biosurfactant-like molecules (BLM) in pathogenicity. The aim of this study is to assess the ability of Shigella environmental and clinical strains to produce BLM and investigate the involvement of biosurfactants in pathogenicity. Our study has shown that BLM are secreted in the extracellular medium with EI24 ranging from 80% to 100%. The secretion is depending on the type III secretion system (T3SS). Moreover, our results have shown that S. flexneri, S. boydii, and S. sonnei are able to interact with hydrophobic areas with 17.64%, 21.42%, and 22.22% hydrophobicity, respectively. BLM secretion is totally prevented due to inhibition of T3SS by 100 mM benzoic and 1.5 mg/ml salicylic acids. P. aeruginosa harboring T3SS is able to produce 100% of BLM in the presence or in the absence of both T3SS inhibitors. The secreted BLM are extractable with an organic solvent such as chloroform, and this could entirely be considered a lipopeptide or polypeptide compound. Secretion of BLM allows some Shigella strains to induce multicellular phenomena like “swarming.”

Invasion of epithelial cells are correlated with secretion of Biosurfactant via the type 3 secretion system (SST3) of Shigella flexneri

Biosurfactants are amphipathic molecules produced by many microorganisms, usually bacteria, fungi and yeasts. They possess the property of reducing the tension of the membrane interfaces. No studies have been conducted on Shigella species showing their involvement of biosurfactant like molecules (BLM) in pathogenicity. This study aims to show that environmental and clinical strains of Shigella are able to produce BLM by emulsifying gasoline and diesel fuels. Our study has shown that BLM are secreted in the extracellular medium with EI24 ranging from 80 to 100%. The secretion is depending on the type III secretion system (T3SS). We did show that S. flexneri, S. boydii and S. sonnei are able to interact with hydrophobic areas with respectively 17.64%, 21.42% and 22.22% of hydrophobicity. 100 mM Benzoic and 1.5mg/mL Salycilic acids have been inhibited T3SS and this totally stops the BLM secretion. Pseudomonas aeruginosa which has T3SS is able to produce 100% of BLM in the presence or in the absence of both T3SS inhibitors. The secreted BLM is extractable with an organic solvent such as chloroform and could entirely be considered like lipopeptide or polypeptidic compound. By secreting BLM, Shigella is able to perform multicellular phenomena like “swarming” allowing to invade and disseminate inside epithelial cells.

IMPACT OF LIPASE ON MICELLE FORMATION AND SOLUBILIZATION ABILITIES OF NON-IONIC SURFACTANTS

Biotechnology is one of the fastest growing sector of scientific and applied activities of the humans, which needs to be successfully integrated into existing technologies. Such upcoming trend is the combination of conventional pulp treatment by surfactants and enzymatic processing in order to prevent pitch troubles in the pulp and paper mills. This article presents the research results of the abilities of non-ionic surfactants (sintamid-5, sintanol DS-10), enzyme (lipase) and their syner-gistic combinations to the micelle formation and solubilization. We chose the optimal synergistic compositions and investigated their colloid-chemical characteristics. There is no effect to the micelle formation ability of surfactants when addition of lipase is up to 30%. The largest deviation from the additive values of surface activity was observed for the mixture of individual non-ionic surfactant and lipase at the ratio of 70:30. However, in the all mixtures of both surfactants and lipase the ratio of experimental surface activity to the theoretically calculated is less than one. It looks, that hydrophilic areas of mixed aggregates block hydrophobic areas of lipase thereby preventing adsorption of lipase at the interface. A predominance of the surfactant in the composition will reduce its cost. The maximum of solubilizing capacity has sintanol DS-10 due to its highest HLB and the lowest CMC that leads to more micelles amount in solution and higher total hydrocarbon volume. The pitch solubilization in lipase solutions does not depend on enzyme concentration. The high pitch dissolving in synergistic mixture of sintanol DS-10 and lipase is observed. It is predetermines the usage of such systems for cellulose deresination.For citation:Smith R.A., Demyantseva E.Yu. Andranovich, O.S. Impact of lipase on micelle formation and solubilization abilities of non-ionic surfactants. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 6. P. 54-60

Structural insights into chaperone-activity enhancement by a K354E mutation in tomato acidic leucine aminopeptidase

Tomato plants express acidic leucine aminopeptidase (LAP-A) in response to various environmental stressors. LAP-A not only functions as a peptidase for diverse peptide substrates, but also displays chaperone activity. A K354E mutation has been shown to abolish the peptidase activity but to enhance the chaperone activity of LAP-A. To better understand this moonlighting function of LAP-A, the crystal structure of the K354E mutant was determined at 2.15 Å resolution. The structure reveals that the K354E mutation destabilizes an active-site loop and causes significant rearrangement of active-site residues, leading to loss of the catalytic metal-ion coordination required for the peptidase activity. Although the mutant was crystallized in the same hexameric form as wild-type LAP-A, gel-filtration chromatography revealed an apparent shift from the hexamer to lower-order oligomers for the K354E mutant, showing a mixture of monomers to trimers in solution. In addition, surface-probing assays indicated that the K354E mutant has more accessible hydrophobic areas than wild-type LAP-A. Consistently, computational thermodynamic estimations of the interfaces between LAP-A monomers suggest that increased exposure of hydrophobic surfaces occurs upon hexamer breakdown. These results suggest that the K354E mutation disrupts the active-site loop, which also contributes to the hexameric assembly, and destabilizes the hexamers, resulting in much greater hydrophobic areas accessible for efficient chaperone activity than in the wild-type LAP-A.

Zigzag polymer chains incatena-poly[[[triaqua(isobutyrato-κO)magnesium(II)]-μ-isobutyrato-κ2O:O′] monohydrate]

The structure of the title compound, {[Mg(C4H7O2)2(H2O)3]·H2O}n, features one-dimensional ...(μ2-ib)Mg(μ2-ib)Mg... zigzag chains (ib is isobutyrate) parallel to thecaxis. The octahedral Mg environment is completed by threefac-oriented terminal water ligands, as well as one further monodentate end-on coordinated ib ligand. In the crystal structure, the hydrophobic ib groups are all oriented within one half of the coordination perimeter of each chain, whereas the water ligands, together with hydrogen-bonded noncoordinated solvent water molecules, define the other half. Along theaaxis, neighbouring strands are oriented so that both the hydrophilic and hydrophobic sides are adjacent to each other. This results in an extensive hydrogen-bonding network within the hydrophilic areas, also involving an additional solvent water molecule per formula unit. There are van der Waals contacts between the aliphatic isopropyl groups of the hydrophobic areas.

Amine-rich Silver Complexes of rac-trans-1,2-Diaminocyclohexane

The use of the diamine rac-trans-1,2-diaminocyclohexane (LL) as a major component of the solvent system allows the isolation of crystalline silver complexes with higher ratios of LL to silver (up to 4 : 1, compared to the previously obtained 1 : 1 in ethanolic solution). The complexes obtained and crystallographically characterized were (LL)2AgNO3 (1), (LL)3Ag(OAc)(H2O)2 (2) and (LL)4AgBr(H2O)3 (3). Additionally, the silver-free compounds (LL)・(H2O) (4) and (LL)3・HCl (5) were obtained as by-products. Complex 1 is a chain polymer with one bridging and one terminal LL ligand; the chains are homochiral. Complex 2 contains isolated [(LL)3Ag]+ cations with one chelating and two monodentate ligands. Complex 3 contains dimeric [(LL)2AgBr]2 units; the additional LL molecules are not coordinated to the metal. Compound 5 consists of one diamine with imposed twofold symmetry, one half-protonated diamine in which the acidic hydrogen site is half-occupied (it is involved in a disordered hydrogen bond N-H・ ・ ・N across a twofold axis) and a chloride anion on a twofold axis. In all five structures, the components pack so as to form clearly defined hydrophilic and hydrophobic areas. In the former, classical hydrogen bonds are formed. Except for a few borderline cases of three-center bonds, these are all two-center systems. The appreciable number of these (e. g. 20 for compound 3) renders the layer structures quite complex, but in most cases they can be analyzed in terms of smaller units.

Influence of carbon source and surface hydrophobicity on the aggregation of the yeastKluyveromyces bulgaricus

Aggregation of the yeast Kluyveromyces bulgaricus is mediated by the galactose-specific lectin KbCWL1. This lectin contains hydrophobic amino acids and its activity is calcium dependent. A specific fluorescent probe, 1-anilinonaphthalene-8-sulfonic acid in the free acid form (ANS; Sigma Chemical Co., St. Louis, Missouri), was used to study the hydrophobic areas on the cellular surface of K. bulgaricus. Changes in surface hydrophobicity during the growth and aggregation of yeast cells were studied. Surface hydrophobicity increased during growth and depended on the amount of yeast cells in the culture medium. During growth, the size of the hydrophobic areas on the cell surface was measured using ANS and was found to increase with the percentage of flocculating yeasts. Our results strongly suggest that the hydrophobic areas of the cell walls of yeast cells are involved in the aggregation of K. bulgaricus.Key words: aggregation, carbon source, fluorescence probe, hydrophobicity, yeast.