Sharif Digital Repository

Penicillin G Acylase is the key enzyme in producing semi-synthetic antibiotics such as Ampicillin and Amoxicillin. In this study, we used E.coli ATCC 11105 in order to produce it. This enzyme was an intracellular one which was produced under suitable conditions. Crude enzyme was released after cell disruption by ultrasonic waves (sonication method) and was partially purified by ammonium sulphate precipitation. Immobilization is investigated at different pHs around the iso-electric pH of Penicillin G Asylase enzyme. Therefore, optimum pH and optimum concentration of ammonium sulphate cuts were determined. Also immobilization process of this enzyme was studied on chitosan polymer, activated by... 

The bio-oxidation of ferrous iron is a potential industrial process in the regeneration of ferric iron and the removal of H2S in combustible gases. Bio-oxidation of ferrous iron may be an alternative method of producing ferric sulfate, which is a reagent used for removal of H2S from biogas, tail gas and pulp and paper industry. For practical use of this process, this study evaluated the optimal pH and initial ferric concentration. pH control looks like a key factor as it acts both on growth rate and on solubility of materials in the system. Some process variables such as pH and amount of initial ferrous ions on oxidation by A. ferrooxidans and the effects of such process variables dilution... 

The enzyme L-Asparaginase (L-asparagine amidohydrolase, EC 3.5.1.1) has been thoroughly researched by many researchers worldwide because of its immensely useful medical applications. It can catalyze the hydrolysis of L-asparagine to L-aspartic acid and ammonia that is effective for the cure of leukemia, especially for puerile Acute Lymphocytic Leukemia [ALL] and Lymphosarcomas. The present study discusses the studies carried out for the optimal production of the enzyme from Escherichia coli ATCC 11303. For extraction of the intracellular enzyme, Sonication is more useful method for cell disruption than alkali lysis and enzymatic method. We improved Luria Bertani (LB) media (tryptone 1% w/v,... 

Xylitol is a sugar alcohol or polyol that has been used as a food additive and sweetening agent due to Its high sweetening power, anti-cariogenic properties and possibilities for use in diabetic food products, makes xylitol an attractive sucrose substitute in a wide variety of foods and beverages. Xylitol is a five carbon polyol or pentitol obtained by the hydrogenation of xylose. xylitol could be produced from xylose in rice seed coats medium by Saccharomyces cerevisiae. For xylitol production, S.cerevisiae was grown in preculture medium at 30°C and agitated at 120 rpm on a rotary platform shaker. The cells were harvested after 20hr, were centrifuged and transferred to the production... 

Application of nanoparticles in targeted delivery and controlled drug release is recently highly attracted especially in cancer therapy. In this study with the aim of developing a novel drug vector based on metallic nanoparticles, gold nanoparticles with their unique characteristics were used to design a vector for targeted anti-cancer drug delivery to tumor. First, gold nanoparticles were chemically synthesized therough sodium citrate and sodium brohydrate reductions with average diameters of 22 and 11 nm, respectively. Then, the activated poly ethylene glycol (PEG) and activated folic acid were conjugated to the lysine-capped gold nanoparticles. Subsequently, the widely used anticancer... 

Nanocomposite films based on low density polyethylene (LDPE), containing of 2, 3, and 4 wt% organoclay (OC) and ethylene vinyl acetate (EVA) copolymer as a new compatibilizer were prepared and characterized using X-ray diffraction, tensile tests, and oxygen permeation measurements. There was no exfoliation or intercalation of the clay layers in the absence of EVA, while an obvious increase in d-spacing was observed when the samples were prepared with EVA present. This issue was reflected in the properties of nanocomposites. The oxygen barrier properties of the OC/EVA/LDPE film were significantly better than those of the OC/LDPE film. The average aspect ratio of clay platelets in... 

Biodegradation has always been as a proper method for treatment of oil contamination. Accordingly, several investigations have been done by mesophilic bacteria for biodegradation of hydrocarbons while few studies have been conducted about thermophilic bacteria.
There are many factors like high growth rate of thermophilic bacteria and good resistance of enzymes secreted from thermophiles against physical and chemical variations lead to the extensive use of thermophilic bacteria for removal of oil contamination. The important factors should be optimized in order to choose a suitable method for the removal of oil contaminations. Optimal conditions for oil contamination removal by... 

Fats and oils are one of the main human food diet components that provide the necessary fatty acids for our body. So the fatty acids available in consuming oils are so important. In this research the mixture of palm and sunflower oils with different compounds: (80:20, 60:40, 50:50, 40:60, 20:80) were used for preparing free- trans shortening by interesterification. For this purpose a special stabilized lipase (Lipozyme TLIM) were used and performed the physicochemical properties: free fatty acids, peroxide value, iodine value, slip melting point, solid fat content, P-anisidine value, soap, oxidative stability at 110 0C, and the profile of fatty acids on the primitive blends and final samples... 

In this research, carbon nanotubes (CNTs) and CNT coated by titanium dioxide (TiO2) were used as adsorbents for desulfurization. Photocatalytic oxidation by titanium dioxide Degussa P-25 nanoparticles (as photocatalyst) immobilized on a porous and low-density support called “perlite” and CNT/TiO2 was perused. TiO2-coatings were prepared by liquid phase deposition method.This is a wet process for the formation of metal oxide thin films on substrates. The coating of nanotubes with TiO2 was confirmed by IR and EDAX and morphological properties were observed by SEM analysis.The physical properties of adsorbents were determine using BET.Dibenzothiophene (DBT)dissolved in acetonitrile was used as... 

This research relates to an improved method for making surfactant esters, especially sorbitan monostearate and tristearate. Sorbitan esters of fatty acid, stearate are derived from a reaction between sorbitan and fatty acid. Sorbitan fatty acid ester called sorbitan ester, are surfactants highly safe to use on human body and are widely used as a food additive in the production process as emulsifiers. Sorbitan esters are well known emulsifiers suitable for use in food, pharmaceutical products as well as many other applications. Despite its simple name, sorbitan ester is complex mixture of molecules. One such technique involves direct esterification of sorbitol or an intramolecular condensate... 

Oil refineries, petrochemical factories and oil platforms produce a large amount of oily wastewater every day. If these wastewaters are released in environment, it can damage soil and water seriously. Although, Biological treatment of oily wastewaters is a well-established method for remediation of these wastes, efficiency of conventional systems such as Activated Sludge, aren’t very high. Also these systems have many problems such as instability during hydraulics shocks and bulking phenomena. the hybrid bioreactor system are designed to increase the efficiency of treatment by allowing greater organic loads, increasing microbial concentration by using attached and suspended bacteria, and... 

In this study, Pseudomonas aeruginosa BBRC-10036 was used for lipase production. The organism secreted the enzyme extracellulary. First of all, effect of initial pH of the culture broth on lipase activity was studied in order to determine the optimum condition for lipase production. After production, this enzyme must be separated from culture and after that the enzyme must be purified for using in analysis and industry. Different methods are used for purification of the enzyme. In this research, first precipitation was used and then this lipase has been purified by Ion exchange Chromatography leading to 2.33- fold purification and 11.47% recovery. In precipitation by acetone, maximum... 

In this project an enzymatic peroxidase biosensor based on two naono structured material 1-Polyaniline nananofibers 2-Polyethylene glycol-Poly citric acid copolymer was studied for phenol detection.Polyaniline nanofibers and poly ethylene glycol-poly citric acid copolymer were synthetized by chemical polymerization.Electrochemical behaviors of these biosensors were studied using cyclic voltammetry (CV) and amperometric techniques. The amperometric response of the coated electrodes is highly stable with 92% of the initial activity remaining after 5 determinations. These phenol biosensors show an oxidation peak at 0.55V. The amperometric response for phenol biosensor based on Polyaniline... 

An antioxidant is a molecule capable of preventing the oxidation of other molecules and neutralizing free radicals. Free radicals are the root cause for many human diseases.Rice bran is one of the most important co-products in the rice milling.In this research antioxidant activity of two Iranian rice bran varieties Fajr and Tarem, extracted by three different solvents (methanol, ethanol and ethyl acetate),determined at different time of extraction by measurement of total phenolic content, free radical scavenging, inhabitation of linoleic acid peroxidation and reducing power. The methanolic extract of Fajr rice bran produced strong results in antioxidant activity. The amount of Total... 

Environmental problems have been one of the considerable issues since the irreversible characteristics of nature and its effect on human life were recognized. Scientists have proposed a variety of solutions in order to overcome such problems. Green marketing can be regarded as one of the solutions in this area. Similar to most other issues, this concept has been noticed less in developing countries compared to developed countries. Therefore, researchers in this study conducted a comprehensive research on the concept of green marketing in Iran focusing on consumers’ behavior.
To achieve relevant results, two types of research were conducted: qualitative and quantitative. The results of... 

Many chemicals exist in the petroleum wastewater, whose disposal into the environment can result in environmental pollutions and serious damages to the ecosystem.Since conventional treatment processes are not sufficient to achieve the water quality requirements, advanced treatment processes are required. In this study, Hybrid Membrane Bioreactor (HMBR), Rotating biological contactor with packing (RBCp) coupled with an external membrane, is used for synthetic petroleum wastewater treatment. Biodegradability of chemical oxygen demand (COD) and that of total petroleum hydrocarbon (TPH) were evaluated and compared for different hydraulic retention times (HRTs) and petroleum pollution... 

Increasing use of polymeric materials, especially in the packaging industry, besides the problems that exist in recycling these materials, has become a serious concern for the environment. The synthetic polymers are used widely in packaging industry so they have a considerable role in waste production in packaging industry. One way to solve this problem is adding a natural polymer to the synthetic polymer, as a result it becomes friendly environmentally. Starch is one of these natural polymers which is cheap and has the ability to complete degradation in the environment.using row starch in the polymeric compounds causes a severe drop in compound’s properties. For this reason, row starch must... 

Peppermint oil is one of the most often used food ingredients and it is volatile. Many common procedures such as microencapsulation have been used for protecting volatile food ingredients. For this research, L-menthol was chosen as the core material to be encapsulated. L-menthol is responsible for the minty flavor and cooling sensation of food and pharmaceutical products. The encapsulation of L-menthol was prepared by complex coacervation, using gum Arabic and gelatin as wall material and tannic acid as cross-linking agent. The effect of various processing parameters, including wall material, core material, tannic acid and tween¬80 concentrations, on particle size and efficiency was... 

Nowadays bioethanol is one of the main factors in the fuel market. It is currently produced from sugars and starchy materials, but lignocelluloses can be expected to be major feedstocks for ethanol production in the future. Agricultural residues such as wheat straw are being considered a potential lignocellulose raw material for fuel-ethanol production as an alternative to starch or sugar-containing feedstock. In order to produce bioethanol, it is necessary to decompose the wheat straw into soluble sugars. But lignocellulosic materias needs pretreatment before hydrolysis and fermentation. The main goal of pretreatment is to increase the enzyme accessibility improving digestibility of... 

After primary and secondary recovery processes more than 50 percent of oil remains in reservoirs. Therefore for more recovery from these reservoirs, methods of enhanced oil recovery should be applied.In this paper the effect of nanoparticles of SiO2 in size of 14 nm, on wettability is investigated. Using this nanoparticle, the wettability of carbonate rock in reservoirs could be changed and alter from oil-wet or mix-wet to water-wet. To assess this, hydrophilic changes of sandstone core and carbonate core are studied using the contact angle test. The same test is done on the carbonate core saturated with brine and oil that had received injection with brine and nanoparticles of SiO2 with two...