Effect of Organic Solvents on the Activity, Stability and Secondary Structure of asclepain cI, Using FTIR and Molecular Dynamics Simulations.

The present study aims at understanding the effect of organic solvents on the specific proteolytic activity and operational stability of asclepain cI in aqueous-organic media, using correlations between geometrical and structural parameters of asclepain cI. These correlations were determined by molecular dynamics (MD) simulations and the secondary structure of the enzyme validated by Fourier-transform Infrared (FTIR) spectroscopy. Asclepain cI exhibited significantly higher catalytic potential in 29 of the 42 aqueous-organic media tested, composed by 0.1 mM TRIS hydrochloride buffer pH 8 (TCB) and an organic solvent, than in buffer alone. Asclepain cI in water-organic miscible systems showed high FTIR spectral similarity with that obtained in TCB, while in immiscible systems the enzyme acquired different secondary structures than in buffer. Among the conditions studied, asclepain cI showed the highest catalytic potential in 50% v/v ethyl acetate in TCB. According to MD simulations, that medium elicited solvation and flexibility changes around the active center of asclepain cI and conducted to a new secondary structure with the active center preserved. These results provide valuable insights into the elucidation of the molecular mechanism of asclepain cI tolerance to organic solvents and pave the way for its future application for the synthesis of peptides in aqueous-organic media.

Label-Free Detection of Unbound Bilirubin and Nitrophenol Explosives in Water by a Mechanosynthesized Dual Functional Zinc Complex: Recognition of Picric Acid in Various Common Organic Media.

High levels of unconjugated bilirubin (UB) in serum lead to asymptomatic and neonatal jaundice and brain dysfunctions. Herein, we have reported the detection of UB at as low as 1 µM in an aqueous alkaline medium using a Zn(II) complex. The specificity of the complex has been validated by the HPLC in the concentration window 6-90 µM, which is rare. The sensory response of the probe at physiological pH against nitro explosives developed it as an instant-acting fluorosensor for picric acid (PA) and 2,4-dinitrophenol (2,4-DNP). Spectroscopic titration provided a binding constant of 4×105  M-1 with PA. The naked eye detection was found to be 15 µM. The solid-state photoluminescent nature of the complex enabled it for PA sensing in the solid phase. Interestingly, the probe remained fluorescent in various volatile and non-volatile organic solvents. As a result, it can also detect PA and 2,4-DNP in a wide range of common organic media. NMR studies revealed the coordination of PA, 2,4-DNP, and UB to the Zn(II) center of the probe, which is responsible for the observed quenching of the probe with the analytes.

Dyeing wastewater treatment in horizontal-vertical constructed wetland using organic waste media.

A hybrid constructed wetland (CW) system with horizontal and vertical flow combination was evaluated for treating carbon-deficient synthetic dyeing wastewater containing 100 mg/L Reactive Yellow 145 dye. Organic waste products such as cow manure and wood chips were added as media in horizontal CW, and gravel as vertical CW media. Horizontal and vertical CWs were planted with Typha angustifolia. Horizontal CW was operated in continuous mode at hydraulic retention time (HRT) of 3 d and vertical CW in batch mode at 1 d HRT. The results suggested the potential application of a cost-effective horizontal-vertical hybrid CW to remove azo dyes from low-carbon dyeing wastewater. In horizontal CW, organic media was used as the carbon source for microbial dye degradation, resulting in 90% colour removal in the absence of available carbon in dyeing wastewater. Proteobacteria, Firmicutes and Bacteroidetes played a dominant role in dye degradation in horizontal CW. Vertical CW removed dye degradation organics, 69% ammonium-nitrogen and 39% organic-nitrogen. Phytotoxicity assays indicated toxicity reduction along the CW treatment path.

The leaching behaviour of herbicides in cropping soils amended with forestry biowastes.

Leaching of herbicides in cropping soils not only impacts the groundwater sources but also reduces their effect in controlling weeds. Leaching studies were carried out in two cropping soils and two forestry biowaste media, wood pulp and sawdust with two herbicides, atrazine and bromacil in a packed lysimeter with simulated rainfall. The hypothesis was that high organic matter forestry biowaste soil amendments reduce the leaching of herbicides through the soil profile. Results from the experimental setups varied due to the impact of the simulated rainfall on the surface structure of the media. Organic carbon content, pH and structure of the media were all factors which affected the leaching of the two herbicides. The hypothesis was true for wood pulp, but for sawdust, organic matter content had less bearing on the leaching of the herbicides than other over-riding factors, such as pH, that were media specific. In sawdust, its large particle size and related pore volume allowed preferential flow of herbicides. Overall, the data indicated that both forestry biowastes were retentive to herbicide leaching, but the effect was more pronounced with wood pulp than sawdust.

Synthesis and characterization of novel acylthiourea compounds used in ions recognition and sensing in organic media.

A series of novel N-acyl-N'-aryl thiourea derivatives were designed and prepared with the aim to develop dual responsive receptors for anions and cations. The structure of the new products was confirmed by NMR spectroscopy (13C and 1H), elemental analysis, and IR spectroscopy. Their thermal stability was studied by thermogravimetric analysis (TG) and it was found that these acyl thiourea derivatives are stable up to 160 °C. The ion recognition and sensing properties of the acyl thiourea compounds were investigated by UV-VIS absorption spectroscopy in organic media upon the addition of various salts. The UV-VIS studies revealed that these acyl thiourea derivatives are able to sense biological important ions such as fluoride and copper (II) ions.

Evaluation of biological activities, structural and conformational properties of bovine beta- and alpha-trypsin isoforms in aqueous-organic media.

The study of the biological activity of trypsin isoforms in aqueous-organic media is of great interest to various fields of knowledge and biochemistry applications. Thus enzymatic, structural, and energetic properties of bovine ß- and α-trypsin isoforms were compared in aqueous-organic media using 30 mg of each isoform. The results showed that the changes induced on the structure and activity of the same trypsin isoform occur at different concentrations. Better results for activity (ionic strength of 0.11 mol·L-1, at 37 °C and pH 8.0) were found in 0-40% of ethanolic media in which the activity for ß-trypsin was about 60% higher than ɑ-trypsin. The ethanolic system does not cause significant changes in the level of secondary structure but the ß-trypsin isoform undergoes a major rearrangement. The use of until 60% (v/v) ethanol showed that ß-trypsin presents a denaturation process 17% more cooperative. The organic solvent causes redistribution in the supramolecular arrangement of both isoforms: all concentrations used induced the ß-trypsin molecules to rearrange into agglomerates. The ɑ-trypsin rearranges into agglomerates up to 60% (v/v) of ethanol and aggregates at 80% (v/v) of ethanol. Both isoforms keep the enzymatic activity up to 60% (v/v) of ethanol.

Enzymatic synthesis optimization of isoamyl butyrate from fusel oil

Many food, cosmetic and pharmaceutical industries have increased their interest in short-chain esters due to their flavor properties. From the industrial standpoint, enzyme reactions are the most economical strategy to reach green products with neither toxicity nor damage to human health. Isoamyl butyrate (pear flavor) was synthesized by isoamyl alcohol (a byproduct of alcohol production) and butyric acid with the use of the immobilized lipase Lipozyme TL IM and hexane as solvents. Reaction variables (temperature, butyric acid concentration, isoamyl alcohol:butyric acid molar ratio and enzyme concentration) were investigated in ester conversion (%), concentration (mol L-1) and productivity (mmol ester g-1 mixture . h), by applying a sequential strategy of the Fractional Factorial Design (FFD) and the Central Composite Rotatable Design (CCRD). High isoamyl butyrate conversion of 95.8% was achieved at 24 hours. At 3 hours, the highest isoamyl butyrate concentration (1.64 mol L-1) and productivity (0.19 mmol ester g-1 mixture . h) were obtained under different reaction conditions. Due to high specificity and selectivity of lipases, process parameters of this study and their interaction with the Lipozyme TL IM are fundamental to understand and optimize the system so as to achieve maximum yield to scale up. Results show that fusel oil may be recycled by the green chemistry process proposed by this study.

Performance of organic substrate amended constructed wetland treating acid mine drainage (AMD) of North-Eastern India.

A horizontal subsurface flow constructed wetland (HSSF-CW) was evaluated for the remediation of synthetic acid mine drainage (AMD) using an organic-rich substrate (cow manure and bamboo chips) planted with common cattail. The synthetic AMD simulated the source AMD generated in North Eastern Coalfield of Assam, India. The synthetic AMD was highly acidic (pH < 2.5) and contained heavy metals (Fe, Mn, Al, Co, Ni and Cr) and sulfate (900-1500 mg L-1). HSSF-CW was operated under varying levels of AMD concentration (10, 25, 40, 70 and 100%) during the acclimatization and thereafter continued to operate at full strength AMD at hydraulic retention time of 7 days. After the 6-month experiment, the results suggested the potential application of HSSF-CW due to its ability to raise the pH from 2.1 to 6.4 with the simultaneous removal of metals (except for manganese) and microbial sulfate reduction (44-75%). Metal removal efficiency in the order: chromium (99.7%) > nickel (97.8%) > cobalt (93.7%) > iron (91.6%) > aluminium (59.7%). Toxicity Characteristic Leaching Procedure test (TCLP) study suggested very negligible leachability of chromium for safe disposal. Common cattails exhibited poor bioaccumulation and translocation for all heavy metals except for manganese and cobalt.

Effect on herbicide adsorption of organic forestry waste products used for soil remediation.

Organic soil amendments can be useful for improving degraded soil, but this increase in organic matter (OM) may influence adsorption of herbicides subsequently applied to the treated soil, even though the particle size of amendments and their nature differ from typical soil OM. In this study, a batch equilibrium method was used to measure adsorption of five herbicides following application to two organic media, wood pulp and sawdust, comparing these with two cropping soils. Herbicide adsorption, quantified by distribution coefficients (kd), was much higher in the two organic media than in the cropping soils. The increases in adsorption were strongly correlated to the percentage of organic carbon. When the kd was normalized to adsorption coefficients corrected for OM content (koc), variation in results between the media was greatly reduced, indicating that OM is an important factor influencing adsorption in these media. The results of this study suggest that herbicides will be less effective when applied to soils in which sawdust and wood pulp have been added. Using organic amendments to remediate soil will increase adsorption of pesticides, reducing their bio-availability and efficacy, but also reducing their tendency to leach into root zones of deep-rooted crops and into groundwater.

The use of biochar and crushed mortar in treatment wetlands to enhance the removal of nutrients from sewage.

An experimental study was carried out using in pilot-scale constructed wetland systems, operated in parallel to treat raw sewage. Each system consisted of a vertical flow (VF) unit that was filled with biochar as the main media, followed by a horizontal flow (HF) unit filled with crushed cement mortar. Hydraulic loading (HL) ranged 340-680 mm/day was applied on the VF wetland units, where high total nitrogen (TN) mass removal rate (20-23 g N/m2 d) was obtained, demonstrating that biochar media had a beneficial effect on the degradation of nitrogenous pollutants. Total phosphorus (TP) removal percentage (concentration based) was ≥ 86% in HF wetlands packed with mortar materials. In one system, the flow direction of the sewage was directed by the deployment of downflow pipes and vertical baffles, aiming to facilitate the formation of aerobic and anaerobic zones in the wetland matrices. The effects of such arrangement were analyzed by comparing pollutant removal efficiencies in the two systems. On average, 99, 96, 93, and 86 percentage removals were obtained for ammonia (NH4-N), TN, biochemical oxygen demand (BOD), and TP, respectively, during the experiments. Biochar and crushed mortar proved to be a highly effective combination as media in subsurface flow constructed wetlands for wastewater treatment.

Organic Media Superwettability: On-Demand Liquid Separation by Controlling Surface Chemistry.

Superwettability involving water affinity has demonstrated prominent advantages in oil-water separation. However, superwetting surfaces in nonpolar liquid-polar liquid systems are rarely explored for the separation of organic liquids. In this work, a protocol of elaborately controlling surface chemistry is presented to construct dual superlyophobic surfaces for polar or nonpolar liquids in opposite organic media. On two kinds of silver-roughened copper coatings, a polar hydroxyl group is subtly integrated with nonpolar perfluoroalkyl chain at the nanoscale. Prewetted by one organic liquid, the obtained dual superlyophobic mesh can selectively intercept other immiscible organic liquids, realizing high-efficiency on-demand separation. In theory, the dual superlyophobic surfaces in organic media are strongly dependent on their affinity toward polar liquids and the surface roughness. The discovery may promote the development of organic liquid-related interfacial materials.

Immobilized cutinases: Preparation, solvent tolerance and thermal stability.

Developing active immobilized enzymes and characterization of their use conditions is critically important prior to initiating studies of enzyme selectivity and substrate specificity in organic media. To this end, physical immobilization by hydrophobic interactions was performed with three well-characterized cutinases (Aspergillus oryzae Cutinase (AoC), Humicola insolens Cutinase (HiC), and Thielavia terrestris Cutinase (TtC)) using Lewatit VP OC 1600 as the macroporous support. We found that immobilization yields >98% were achieved for all three cutinases under the following immobilization conditions: 100 mg/g loading ratio, immobilization buffers of 100 mM phosphate pH 8 (AoC and HiC) and 100 mM acetate pH 5 (TtC), mixing at 150 rpm and 30 °C for 24 h. Among the three cutinases, HiC has the highest tolerance towards solvents of increased polarity while TtC has the highest thermal stability (up to 80 °C) in a bulk reaction system that consists of the reactants butanol and lauric acid. In nonane, these cutinases retain >64% of their activity at 90 °C. Furthermore, kinetic stability (residual activity as a function of time) analysis reveals that the cutinases retain >75% residual activity at 70 °C in 3 h. Moreover, at 80 °C, the kinetic stability of TtC is higher than that of HiC and AoC. Collectively, the results herein set the stage for the in-depth evaluation of these catalysts for selective transformations in organic media.

A Sensitive Microbead-Based Organic Media-Assisted Method for Proteomics Sample Preparation from Dilute and Denaturing Solutions.

We developed a robust and sensitive sample preparation method for proteomics termed microbead-based and organic-media-assisted proteolysis strategy (BOPs). BOPs combines two advantages of current techniques, (1) unbiased binding of reversed-phase polymeric microbeads to any type of protein and (2) enhanced trypsin digestion efficiency in CH3CN-aqueous solvent systems, into a single-tube workflow. Compared with conventional techniques, this method effectively concentrates proteins and improves proteolytic digestion, and can be used with submicromolar protein samples in dilute or denaturing solutions, such as 70% formic acid, 8 M urea, or 7 M guanidine hydrochloride without any sample pretreatment. Proteome analysis of single Caenorhabditis elegans organisms demonstrates that BOPs has the sensitivity, reproducibility, and unbiasedness required to characterize worm proteins at a single organism level. We also show that, by simply incorporating an acetone washing step for detergent removal, BOPs is applicable to low concentration samples contaminated with a variety of detergents, including sodium dodecyl sulfate, with negligible protein loss. Moreover, the utility of this modification has also been demonstrated through proteomic characterization of 2000 human (HEK293T) cells lysed using 1% Triton X-100. The simplicity and availability of the present BOPs make it especially attractive for next-stage proteomics of rare and sample-limited systems.

Lipase catalysis in organic solvents: advantages and applications.

Lipases are industrial biocatalysts, which are involved in several novel reactions, occurring in aqueous medium as well as non-aqueous medium. Furthermore, they are well-known for their remarkable ability to carry out a wide variety of chemo-, regio- and enantio-selective transformations. Lipases have been gained attention worldwide by organic chemists due to their general ease of handling, broad substrate tolerance, high stability towards temperatures and solvents and convenient commercial availability. Most of the synthetic reactions on industrial scale are carried out in organic solvents because of the easy solubility of non-polar compounds. The effect of organic system on their stability and activity may determine the biocatalysis pace. Because of worldwide use of lipases, there is a need to understand the mechanisms behind the lipase-catalyzed reactions in organic solvents. The unique interfacial activation of lipases has always fascinated enzymologists and recently, biophysicists and crystallographers have made progress in understanding the structure-function relationships of these enzymes. The present review describes the advantages of lipase-catalyzed reactions in organic solvents and various effects of organic solvents on their activity.

Accurate Diffusion Coefficients of Organosoluble Reference Dyes in Organic Media Measured by Dual-Focus Fluorescence Correlation Spectroscopy.

Dual-focus fluorescence correlation spectroscopy (2fFCS) is a versatile method to determine accurate diffusion coefficients of fluorescent species in an absolute, reference-free manner. Whereas (either classical or dual-focus) FCS has been employed primarily in the life sciences and thus in aqueous environments, it is increasingly being used in materials chemistry, as well. These measurements are often performed in nonaqueous media such as organic solvents. However, the diffusion coefficients of reference dyes in organic solvents are not readily available. For this reason we determined the translational diffusion coefficients of several commercially available organosoluble fluorescent dyes by means of 2fFCS. The selected dyes and organic solvents span the visible spectrum and a broad range of refractive indices, respectively. The diffusion coefficients can be used as absolute reference values for the calibration of experimental FCS setups, allowing quantitative measurements to be performed. We show that reliable information about the hydrodynamic dimensions of the fluorescent species (including noncommercial compounds) within organic media can be extracted from the 2fFCS data.

Crosslinked plastic scintillators: a new detection system for radioactivity measurement in organic and aggressive media.

The measurement of radioactive solutions containing organic or aggressive media may cause stability problems in liquid and plastic scintillation (PS) techniques. In the case of PS, this can be overcome by adding a crosslinker to the polymer structure. The objectives of this study are to synthesise a suitable crosslinked plastic scintillator (C-PS) for radioactivity determination in organic and aggressive media. The results indicated that an increase in the crosslinker content reduces the detection efficiency and a more flexible crosslinker yields higher detection efficiency. For the polymer composition studied, 2,5-diphenyloxazole (PPO) is the most adequate fluorescent solute and an increase in its concentration causes little change in the detection efficiency. The inclusion of a secondary fluorescent solute 1,4-bis-2-(5-phenyloxazolyl) benzene (POPOP) improves the C-PS radiometrical characteristics. For the final composition chosen, the synthesis of the C-PS exhibits good reproducibility with elevated yield. The obtained C-PS also displays high stability in different organic (toluene, hydrotreated vegetable oil (HVO) and methanol) and aggressive media (hydrochloric acid, nitric acid and hydrogen peroxide). Finally, the C-PS exhibits high detection efficiency both in water and in aggressive media and can also be applied in organic media showing similar or even higher detection efficiency values.

Molecular photovoltaics in nanoscale dimension.

This review focuses on the intrinsic charge transport in organic photovoltaic (PVC) devices and field-effect transistors (SAM-OFETs) fabricated by vapor phase molecular self-assembly (VP-SAM) method. The dynamics of charge transport are determined and used to clarify a transport mechanism. The 1,4,5,8-naphthalene-tetracarboxylic diphenylimide (NTCDI) SAM devices provide a useful tool to study the fundamentals of polaronic transport at organic surfaces and to discuss the performance of organic photovoltaic devices in nanoscale. Time-resolved photovoltaic studies allow us to separate the charge annihilation kinetics in the conductive NTCDI channel from the overall charge kinetic in a SAM-OFET device. It has been demonstrated that tuning of the type of conductivity in NTCDI SAM-OFET devices is possible by changing Si substrate doping. Our study of the polaron charge transfer in organic materials proposes that a cation-radical exchange (redox) mechanism is the major transport mechanism in the studied SAM-PVC devices. The role and contribution of the transport through delocalized states of redox active surface molecular aggregates of NTCDI are exposed and investigated. This example of technological development is used to highlight the significance of future technological development of nanotechnologies and to appreciate a structure-property paradigm in organic nanostructures.