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Research subject: In recent years, there are so many attractions in the field of effective detection and discrimination of volatile organic compounds (VOCs). Detection of VOCs compounds, are very important in many applications and industries such as air pollution control, air quality control, food packaging, food quality control, disease diagnostic, agriculture etc. The sensitivity and selectivity of the prepared sensors to detect of VOCs needs to improve.   
 Research approach: A conductive polymer composite sensitive layer based on poly (lactic acid) as polymer matrix and multiwall carbon nanotubes as conductive filler was prepared to detect of volatile organic compounds (VOCs). For this purpose the porous sensitive layer was prepared by non-solvent induced phase separation (NIPS) method. In this structure, chloroform (low boiling point temperature) was used as the solvent and ethanol (high boiling point temperature) was used as a non-solvent. The sensitive layer was used to detect of toluene, methanol, and chloroform. The structure and morphology of synthesized layer was investigated by means of scanning electron microscopy (SEM) and BET test.
Main results: The investigation indicated that the phase separation method induced the open cell morphology into the conductive composite. The BET results showed that the specific surface area of composite increased to 22.3 m²/gr. The experimental results showed that the response properties of porous layers was improved dramatically in comparison with dense layers. It was related to the increase of specific surface area of polymer composite and therefore the increase of diffusion coefficient of analyte molecules into the polymer matrix. Finally the sensitivity and selectivity of porous sensitive layers was investigated based on Flory-Huggins interaction parameter.
 

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The increasing production and use of fossil fuels increase the probability of soil source contamination by oil and petroleum products, and pose a hazard to life. There are over 43,000 chemical contaminated sites in Canada and USA, with 2,200 of them classified as high risk. In the US, over $10 billion are spent annually on the cleanup of contaminated sites. The primary objective of this study was to develop and test an innovative in situ soil washing system that could extract contaminants from the soil, quickly and effectively, without causing any threat to water sources. We proposed the use of an organic solvent in our system that is not only lighter than water but is also immiscible with water. It was in-troduced into the soil profile from below using a system of horizontal, underground per-forated pipes, and collected from the soil surface. Since the solvent was being introduced from the bottom, it “wete” the soil completely and thus removed the contaminant effec-tively. To understand and evaluate the performance of the system for remediation, a pre-liminary experiment was performed using two stainless steel columns (1m long x 0.2m di-ameter) packed with two diesel fuel contaminated soils (fresh and old contamination). The proposed technique is innovative, unique and very fast for the remediation of diesel fuel contaminated soils. It is the first study of its kind employing a subirrigation system for de-livering organic solvents (lighter than water and immiscible in water) for in situ soil wash-ing. Some preliminary applications of the system to diesel fuel contaminated sand soils have proved very promising for both fresh and old contaminated sites. The method could be equally suited for other contaminants also.

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The use of enzymes in organic solvents has biotechnological and industrial importance. Organic solvents can decrease the stability of enzymes that is a challenge for the use of enzymes in organic media. There are several approaches such as protein engineering, chemical modification, and use of additives for stabilization of enzymes in organic solvents. In this study, activity and stability of trypsin were investigated in the presence of different organic solvents. Then the effect of sucrose on the stability of the enzyme was investigated in the absence and prescence of solvents. The result showed that the activity and stability of trypsin were decreased in the presence of organic solvents. DMF had a lowest effect on the activity and stability of the enzyme. The use of sucrose increased the stability of trypsin in the presence of organic solvents. The stabilization effect of sucrose in the presence of DMF was more than other solvents. Consequently, a mixture of DMF and sucrose is proposed for the use of trypsin in industrial applications.

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The antibacterial and antioxidant activities of methanol and acetone extracts of three marine algae, including Hypnea hamulosa, Gracilaria corticata and Enteromorpha intestinalis wereinvestigated.Antioxidant activities were determined by means of total antioxidant capacity, total phenolic compounds, DPPH radical scavenging activity and ferric reducing antioxidant power. Antibacterial activity was determined using a paper disc diffusion method against pathogenic bacteria, including Listeria monocytogenes, Escherichia coli and Bacillus subtilis. Acetone extract of E. intestinalis showed the highest antioxidant activity and contained the highest phenolic compounds. The highest percentage of DPPH radical scavenging activity was observed in the methanol extract of H. hamulosa (p<0.05). The highest ferric reducing antioxidant power was observed in the methanol extract of Glacilaria (p<0.05). The strongest inhibition (p<0.05) against L. monocytogenes was shown by the methanol extract of E. intestinalis and the highest inhibition against B. subtilis and E. coli was observed in the acetone extract (p<0.05). In conclusion, E. intestinalis extracts showed favorable antioxidant and antibacterial activity suggesting its application in food and pharmacological industries.

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In this research, the possibility of asphaltene separation from the vacuum tower residue using the low cost industrial solvents such as 402, 404, 406, and 410 was investigated. In order to separate asphaltene the IP143/01 and ASTM D 3279-07 separation methods were utilized. In order to find the optimal state of asphaltene precipitation, Design of experiments software with three factors of residence time, the solvent-to-feed ratio and the volume percent of 406 solvent to the total solvent of 406 and 410 were used. The results showed that the effectiveness of each parameter in precipitating the asphaltene attributed to the ratio of solvent to feed, the ratio of solvent 406 to total solvent, and the residence time, respectively and there was a significant interaction between the basic parameters. The best asphaltene precipitation of 5.06% of 7.5% happens at the residence time of 36.97 hours, the ratio of solvent to feed of 35.95 ml/gr and the volume percent of 406 solvent to the total solvent of 27.20%. Asphaltene precipitation percentage for the optimal mixture of industrial solvents was 22.5% lower than the precipitated asphaltene from normal heptane solvent. However, according to the solvents price, industrial solvents (410 and 406) were approximately 50% cheaper than normal heptane, and hence on overall, there was a cost savings of more than 20%

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Laccase enzymes are polyphenol oxidase that catalyze the oxidation of wide range of phenolic components including phenols, polyphenols, aromatic amines and non-phenolic substitution with molecular oxygen as electron acceptor. So these enzymes have biotechnological application such as wastewater treatment system, bioremediation of soil pollution and etc. Result from previous studies showed an increase in thermal stability of bacterial laccase from Bacillus sp. HR03 using site directed mutagenesis and the effect of E188 residue on the surface regions at the interface between domain 1 and 2 in stability was confirmed. The aim of the present work was to investigate the effect of this amino acid substitution on enzyme activity in the presence of dimethyl sulfoxide and dimethylformamide as organic solvents. Compression of kinetic parameters including Kcat / Km ، ∆∆G‡, C50 showed significant increases in the mutant enzyme than wild type enzyme, that industrial application of the enzyme will be easy.

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Solvent extraction and taguchi method were used to optimize conditions for the antioxidant activity of Azolla fern extracts. The independent processing variables were ethanol concentration, extraction time and solid to solvent ratio. Ethanol concentration and solvent to solid ratio significantly affected antioxidant activity measured by the total phenol content (p < 0.05). whereas the extraction time did not significantly affect the activity (p > 0.05). Antioxidant activity of the extracts, determined by the total phenolic content, varied from 5.77 to 16.42 mg acid gallic equivalents/g of dry sample. DPPH scavenging activity percentage ranged from %20.51 to %93.71. Ethanol concentration of %50 and sample to solvent ratio of 1 to 15 were optimal for the highest antioxidant activities measured by the TPC assay and the DPPH method. The optimal extraction time was 48h. The result show that azolla fern is suitable for antioxidant extraction.

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Research subject: With the rapid development of science and technology, cerium and cerium oxide are widely used in various fields, including in the manufacture of aluminum, aluminum alloys, some steels and in permanent magnets, catalysts, Polishing powder, Glass, Cinema, and Ceramic Technology. Solvent extraction is one of the effective techniques for extraction, separation, and purification of cerium.
Research approach: The extraction of cerium­(IV) from sulfuric acid solutions using Cyanex 921 in kerosene was investigated. The different parameters affecting the extraction process of cerium(IV) such as pH of aqueous solutions­, reagent, metal ion concentration, contact time as well as temperature, are separately investigated. Experiments in the pH range of 0.5 to 5.5, at 25±1 ^oC­, using Cyanx 921 in the concentration range of 0.06 to 0.4 mol L^-1, and a mixture of Cyanx 921 and D2EHPA was performed in different ratios.
Main results: From the temperature study, the extraction reaction for Ce­(IV) was found to be exothermic in nature. The results indicated that the effective extraction of cerium(IV) from sulfuric acid solutions cannot be achieved in a single equilibration because the solubility of Cyanex 921 in aliphatic diluents is limited at ambient temperature. To rectify this issue, the possibility of using a synergistic mixture of Cyanex 921 and D₂EHPA as extractant system to recover cerium(IV) from sulfuric acid solutions was investigated. Mixtures of Cyanex 921 and D₂EHPA resulted in synergistic extraction of cerium­(IV) from sulfuric acid solutions. The results indicated that, under experimental conditions, the maximum synergistic coefficient was obtained at the molar ratio of (0.6M D₂EHPA_­/­0.2_­M Cyanex 921) 3.0, and cerium(IV) was extracted into organic phase in the form of Ce(SO₄)(HSO₄₎₂.­Cyanex 921.

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In this study, a Bacillus species was identified from the Dosarri mineral spring in Jiroft microflora. This strain produce clear halo in casein agar media. It has been identified as Bacillus Pumilus (KHB3) based on biochemical tests and 16S rRNA gene sequencing. To enzyme production, this strain was cultured in specific medium for 48 h. Supernatant was partially purified after precipitation with ammonium sulphate (85 %), dialysis and ion exchange chromatography (Q-Sepharose). KHB3 protease was characterized in the presence of different pHs, ions and detergents. Results indicated that the enzyme showed maximum activity and stability in pH 8.0. This enzyme retained about 100 % of its activity in the presence of 1.0 and 1.5 M NaCl. KHB3 protease showed 33 and 10 % increase in protease activity in the presence of MnSO4 and FeSO4. KHB3 protease retained at least 45 % of its activity and stability in the presence of commercial detergents. In addition, it show 12 % increase in enzyme activity in the presence of Banoo detergent. Activity and stability in alkaline pH, organic solvents and detergent compounds show that this protease has high value capacity in detergent industry.

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Firefly luciferase is a light generating enzyme, which is used in different fields of biotechnology and molecular biology. Luciferase has found widespread applications in many areas of genetic analysis such as detecting gene expression, reporter gene assay and proteomics studies such as protein-protein interactions. Despite many advantages, there are some limitations in luciferase-based systems, the most important of which is its low stability. One of the newly developed methods to solve this problem is to take advantage of Deep Eutectic Solvents (DES). One group of DESs is those that composed of organic salts with hydrogen donor, due to which, intermolecular hydrogen bonds cause lower melting point in comparison with each of the component. In this study, we investigated the effects of DES on kinetic properties of wild type and I232R - E354R/Arg356 mutant Lampyris turkestanicus luciferases. For this, both enzymes, wild type and mutant, expressed in BL21, the protein of interest purified through affinity chromatography and used for kinetic studies. Here, we used choline chloride: glycerol as DES. According to the results, the wild type luciferase is much more thermostable in DES than I232R - E354R/Arg356 mutant. Furthermore, the remaining activity of both wild type and mutant luciferases are greater in the presence of DES than those in the absence of DES.

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 The effect of different extraction methods (soxtec apparatus, ultrasound, solvent and wet rendering) on yield, quality and fatty acids composition of oil extracted from the offal of common carp (Cyprinus carpio) was compared. For determination of the oil quality, PV, TBA, FFA, conjugated diene, non-enzymatic browning indexes and fatty acids composition were measured. Results showed that soxtec apparatus had the highest efficiency compared to other extraction methods. In addition, ultrasound extraction had higher yield in comparison to solvent methods. Moreover, the wet rendering method had lower oil yield. The quality indexes of oil extracted with ultrasound had significantly lower quality compared to other extraction methods. Hence, the oil extracted with wet rendering methods had better quality. Oil extracted with all of the methods contained high amounts of MUFA, also oil extracted by ultrasound method had the highest content of DHA and EPA as compared with other extraction methods.

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Aspartic proteases (APs) (EC 3.4.23.X) catalyze the hydrolysis of peptide bonds, a reaction that is fundamental to many biological processes. All of the vertebrate and most of the fungal APs are synthesized as zymogens. Porcine pepsin (EC 3.4.23.1) belongs to the aspartic protease family. Pepsin is a gastric aspartic protease and one of the three principal protein degrading enzymes in the digestive system. Pepsin is an industrial enzyme in the food industry. In this study, thermal stability of pepsin investigated in the different concentrations of aluminium in presence and absence of organic solvents ) butanol, ethanol, 1,4-Butanediol and glycerol). Thermal stability of pepsin increased in the presence of aluminium and decreased in presence of organic solvents ) butanol, ethanol, 1,4-butanediol ) and unchanged in presence of glycerol .Thermal stability of pepsin increased in presence organic solvents with adding of aluminium to its absence. possibly aluminum ions through electrostatic and dative interactions with carboxylate groups of Aspartic acid and Glutamic acid residues are bonded to pepsin structure, and causing to condense enzyme structure which leading to increasing thermal stability of pepsin. Mechanism of increasing thermal stability of pepsin is unknown in presence of aluminium. Therefore, we can reduce the instability of pepsin in presence of organic solvents by
Aluminium.

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Abstract:
Research subject:
The use of deep eutectic solvents (DES) as an effective approach to enhance the performance of polymer membranes in CO₂ gas separation has gained significant attention. Membranes modified with DES are referred to as supported liquid membranes (SLMs).
Research approach:
In this study, two-component (choline chloride/urea) and three-component (choline chloride/urea/DBU) DES were used to improve the efficiency of Pebax-1657 (poly(ether-block-amide)) membranes for separating CO₂ from CH₄ and N₂ gases. Gas permeability tests conducted at 2 bar pressure and 30 °C compared pure membranes with membranes enhanced by 10 wt.% of the two-component DES and 10 wt.% of the three-component DES.
Results:
Results showed that the CO₂ permeability increased from 3.77 barrer for the pure membrane to 4.96 barrer for the 10 wt.% DES two-component membrane, and to 7.101 barrer for the 10 wt.% DES-DBU three-component membrane. The CO₂/N₂ and CO₂/CH₄ selectivities improved from 20.32 and 11.36 for the pure membrane to 38.56 and 13.77 for the DES two-component membrane, and to 40.68 and 14.32 for DES-DBU three-component  membrane, respectively. Moreover, with an increase in feed pressure from 2 bar to 6 and 10 bar, the membrane performance improved. At 10 bar, the CO₂ permeability for the 10 wt.% DES three-component  membrane increased to 16.28 barrer, while the CO₂/N₂ and CO₂/CH₄ selectivities rose to 56.13 and 20.60, respectively. Since the DES-DBU three-component  membrane showed better performance than the DES two-component  membrane and the pure membrane, various weight percentages of this composition were used to further enhance the Pebax polymer membrane. The results indicated that the membrane containing 20 wt.% of the DES-DBU three-component  exhibited the best performance among all tested membranes. At 2 bar pressure and 30 °C, this membrane increased CO₂ permeability to 13.88 barrer and CO₂/N₂ and CO₂/CH₄ selectivities to 51.46 and 18.80, respectively. Furthermore, at 10 bar pressure, the CO₂ permeability reached 21.25 barrer, while the CO₂/N₂ and CO₂/CH₄ selectivities improved to 40.66 and 60.25, respectively. Ultimately, this membrane, compared to other studies, has successfully surpassed the Robeson limit, demonstrating its high potential for applications related to CO₂ gas separation.

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The phenolic compounds of pomegranate (Punica granatum L.) peel extracted by two methods (solvent and ultrasound-assisted) with five solvents (acetone, methanol, ethanol, water and ethyl acetate) were compared with supercritical fluid extraction (SFE). The total phenolic compounds were determined according to the Folin-Ciocalteu reagent using tannic acid as standard. The overall results showed that acetone with sonication produced the maximum amount of phenolic compounds from pomegranate peel extracts (PPE). Furthermore, the effect of the acetone extract of pomegranate peel (0.010-0.050 %) on the stability of soybean oil during heating at 60oC (oven test method) was determined by measuring peroxide and thiobarbitoric acid values. At a 0.050 % level of pomegranate peel extract, its antioxidant activity was greater than 0.02 % of the two synthetic antioxidants butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT). The pomegranate peel extract possessed a relatively high antioxidant activity and might be considered as a rich source of natural antioxidant.

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Brown algae are a valuable source of natural antioxidant compounds, especially Phlorotannins. In this study, the effect of solvent concentration (water / ethanol) on the the amount of Phlorotannin compounds and antioxidant properties of extracts from brown alga Sargassum angustifolium were investigated. The extraction was performed by solvent method at room temperature (28-26 °C) with ethanol/ water solvent with three ratios (30:70), (50:50) and (70:30). The amount of Phlorotannin, total phenolic content, ferric reducing antioxidant power, DPPH radical scavenging activity and total antioxidant capacity of different extracts were evaluated. The results showed that the yield of Phlorotannin extraction was dependent on the solvent concentration and with increasing polarity of the solvent, its amount increased, So its amount in ethanol/ water treatment (30:70) is significantly more than the other two treatments (P<0.05). Also, the highest amount of DPPH radical scavenging activity was obtained in ethanol/ water treatments 50:50 and 70:30 which contained less Phlorotannin. Finally, it was found that the ethanol/ water treatment 30:70 of the brown alga Sargassum angustifolium was a good choice for extracting Phlorotannin compounds as a natural bioactive compound for food and medicine purposes.

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The Stability of protease in organic solvent media has been widely discussed for more than two decades. Proteases can catalyze synthetic reactions in organic media, by this way solvent stabilities of proteases are very important. In this study, we reported a bacterium isolated from hot spring of Geinarje, Iran producing an organic solvent stable protease. Protease producing bacteria were screened on skim milk agar and the formation of a clear zone around the bacterial colony was investigated. Proteolytic activity was assayed by a modified caseinolytic method using casein as a substrate. The best alkaline protease producing bacterium was selected and identified on the basis of 16S rDNA gene sequencing and morphological and biochemical characteristics. The effect of organic solvents, temperature, pH, and NaCl on proteolytic activity were examined. According to phylogenetic analysis, morphological and physiological tests, isolated, the bacterium was identified as a new strain of Brevibacillus borstelensis. This strain was able to produce an extracellular organic solvent-stable protease with 0.53U/ml enzyme activity. After 2 hour incubation at 30°C the protease of Brevibacillus borstelensis AMN was active in wide ranges of organic solvents, and its activity was enhanced in the presence of 25% (V/V) isopropanol. The biochemical properties of the enzyme revealed that the optimal pH and temperature for protease activity were 9.0 and 60°C, respectively. Our finding indicated that these robust properties of protease, like outstanding activity and stability in organic solvents and alkaline medium, might be applicable for various industrial biotechnologies.
 

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Tea and sesame seed oils extracted by different methods (including supercritical fluid extraction (SFE), at a pressure of 350 atm, a temperature of 60oC, a static extraction time of 20 minutes, a dynamic extraction time of 30 minutes and 150 g kg-1 of ethanol as a modifier). Solvent (SE) and ultrasound-assisted solvent extraction (UE)), as natural anti-oxidants, were evaluated during 15 days storage by monitoring their effects on refined sunflower oil at 60oC. The peroxide value (PV) and the thiobarbituric acid (TBA) value were used to assess the antioxidant activity of these extracted oils. The highest extraction yields were from SE and SFE, while UE gave a lower yield. Considering oil extraction yield and antioxidant activity, SE and SFE were the preferred methods. The results showed that tea seed oil had strong antioxidant activity, which was almost equal to sesame oil. Therefore, tea seed oil can be used in the same way as sesame seed oil in fat, oil and other food products as a natural antioxidant to suppress lipid oxidation.