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    Application of the Taguchi method to optimize the process conditions in the production of lipase by Pseudomonas aeroginosa B-3556

    , Article Iranian Journal of Science and Technology, Transaction B: Engineering ; Volume 29, Issue 5 , 2005 , Pages 475-482 ; 03601307 (ISSN) Sabbaghian, E. S ; Roostaazad, R ; Sharif University of Technology
    2005
    Abstract
    Pseudomonas aeoroginosa B-3556 was grown on soy flour based semi-solid media for lipase production. The effect of different factors including medium composition, pH, temperature, mixing intensity and substrate particle size on lipase productivity was analyzed using the Taguchi method in three steps. Based on these analyses the optimum concentrations of soy flour, (NH4)2HPO4, K2HPO4 and MgSO4.7H2O were found be 3%, 3%, 0.5% and 0.21% respectively. Furthermore, optimum values for temperature, pH and the shaking speed were determined as 30°C, 7.1 and 150 rpm. As for the substrate particle size, the best result was achieved when the soy flour had a mesh size cut of 60-70. The influence of the... 

    , M.Sc. Thesis Sharif University of Technology Ebadipour, Nagisa (Author) ; Roosta Azad, Reza (Supervisor) ; Yaghmaei, Soheyla (Co-Advisor) ; Bagheri, Tayyebeh (Co-Advisor)
    Abstract
    Biosurfactants are surface active compounds capable of reducing surface tension and interfacial surface tension. Biosurfactants are produced by a variety of microorganisms. They are promising replacements for chemical surfactants because of biodegradability, non-toxicity and being able to produce from renewable sources. However a major problem of producing biosurfactant in industrial level is their production cost. In this research, by using corn steep liquor as low-cost nitrogen source besides other nitrogen sources, not only production cost reduced but also a higher efficiency achieved. Therefore optimization of biosurfactant production was done by RSM and Box- Behnken method. Results... 

    Development of a sensitive diagnostic device based on zeolitic imidazolate frameworks-8 using ferrocene-graphene oxide as electroactive indicator for pseudomonas aeruginosa detection

    , Article ACS Sustainable Chemistry and Engineering ; Volume 7, Issue 15 , 2019 , Pages 12760-12769 ; 21680485 (ISSN) Shahrokhian, S ; Ranjbar, S ; Sharif University of Technology
    American Chemical Society  2019
    Abstract
    Since Gram-negative bacteria have a predominant role in nosocomial infections, there are high demands to develop a fast and sensitive method for diagnosis of bacteria in clinical samples. To address this challenge, we designed a novel electrochemical biosensor based on aptamers immobilized in engineered zeolitic imidazolate Framework-8 (ZIFs-8) via EDC-NHS chemistry. Cyclic voltammetry and electrochemical impedance spectroscopy techniques were conducted to monitor the electrochemical characterization. With respect to unique π-πinteractions between aptamer and graphene oxide (GO), the differential pulse voltammetry technique was applied with ferrocene-graphene oxide (Fc-GO) as an... 

    Optimization of Lipase Immobilization

    , M.Sc. Thesis Sharif University of Technology Sayyar Kavardi, Sepideh (Author) ; Aalemzadeh, Iran (Supervisor) ; Kazemi, Akhtarolmolouk (Supervisor)
    Abstract
    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... 

    Development of Microorganisms with Improved Biosurfactant Activity

    , Ph.D. Dissertation Sharif University of Technology Bagheri Lotfabad, Tayebe (Author) ; Roosta Azad, Reza (Supervisor) ; Rouholamini Najafabadi, Abdolhossein (Supervisor) ; Akbari Noghabi, Kambiz (Co-Advisor) ; Shahcheraghi, Fereshte (Co-Advisor)
    Abstract
    This thesis discusses the work on the production of a rhamnolipid-type biosurfactant by Pseudomonas aeruginosa MR01, its structural characterization and environmental applications. First, results from analytical approaches for screening of biosurfactant producers suggested the oil spreading method as the fastest, simplest and most consistent analytical method. The second part of the thesis describes the properties of the most efficient biosurfactant-producing bacteria isolated from oil fields in south of Iran and according to it’s biochemical characteristics and partial sequenced 16S rRNA gene affiliated with Pseudomonas aeruginosa. Time course study indicated that the maximum biosurfactant... 

    Processing Fermented Lipase

    , M.Sc. Thesis Sharif University of Technology Asadollahi Chaghoosh, Aida (Author) ; Roosta Azad, Reza (Supervisor) ; Yeganeh Sarkandi, Shahin (Supervisor)
    Abstract
    Lipases (triacylglycerol acylhydrolases) are industrial enzymes that have wide applications in the detergent, pharmaceutical and food industries. Pseudomonas aeruginosa strain is known to be suitable for lipase production due to its stability in organic solvents, resistance to temperature and pH. Lipases are usually secreted extracellularly, and its isolation from the culture medium is very important. The most cost-effective separation method is filtration which is more economical than centrifuge. Here, the use of filtration method is important from two aspects of creating clearance and maintaining enzyme activity. The equipment in this research is the filter press, whose initial tests are... 

    Statistical screening of medium components for recombinant production of Pseudomonas aeruginosa ATCC 9027 rhamnolipids by nonpathogenic cell factory pseudomonas putida KT2440

    , Article Molecular Biotechnology ; Vol. 56, issue. 2 , 2014 , p. 175-191 Setoodeh, P ; Jahanmiri, A ; Eslamloueyan, R ; Niazi, A ; Ayatollahi, S. S ; Aram, F ; Mahmoodi, M ; Hortamani, A ; Sharif University of Technology
    Abstract
    Rhamnolipids (RLs) produced by the opportunistic human pathogen Pseudomonas aeruginosa are considered as potential candidates for the next generation of surfactants. Large-scale production of RLs depends on progress in strain engineering, medium design, operating strategies, and purification procedures. In this work, the rhlAB genes extracted from a mono-RLs-producing strain of P. aeruginosa (ATCC 9027) were introduced to an appropriate safety host Pseudomonas putida KT2440. The capability of the recombinant strain was evaluated in various media. As a prerequisite for optimal medium design, a set of 32 experiments was performed in two steps for screening a number of macro-nutritional... 

    Comparing the Performance of Centrifuge, Membrane Filter and Filter Press for Clarification of Lipase Enzyme

    , M.Sc. Thesis Sharif University of Technology Taher Aslani, Ahmad Reza (Author) ; Rousta Azad, Reza (Supervisor)
    Abstract
    Lipases (Triacyl Glycerol Acyl Hydrolase, EC.3.1.1.3) are multidimensional biocatalysts which have many applications in food industrials, dairy, fats and oils processing, detergents, synthesis of pure chemical and pharmaceutical materials, paper industrial and cosmetics. Generally, industrial enzymes are produced extracellularly, so their separation from a low-cost complex medium (usually used for production) is one of the cost stages in their production process. Filtration is the most economical method of separation in the production of enzymes, but due to the small size of colloidal particles and cell masses present in the fermentation environment, its use is subject to limitations. In... 

    Asphaltenes biodegradation under shaking and static conditions

    , Article Fuel ; Vol. 117, issue. PART A , 2014 , pp. 230-235 ; ISSN: 00162361 Jahromi, H ; Fazaelipoor, M. H ; Ayatollahi, S ; Niazi, A ; Sharif University of Technology
    Abstract
    In this study the biodegradability of asphaltenes was investigated using four bacterial consortia isolated from oil contaminated soils and sludge. The species in consortium 1 were identified as Pseudomonas aeruginosa and Pseudomonas fluorescens. Consortium 2 contained Citrobacter amalonaticus and Enterobacter cloacae. Consortium 3 contained only one species identified as Staphylococcus hominis, and the species in consortium 4 were identified as Bacillus cereus, and Lysinibacillus fusiformis. Spectrophotometry at 281 nm wavelength was applied to quantify asphaltenes biodegradation. The biodegradation tests were performed in flasks with the initial asphaltenes concentrations of 2, 4, 10, 20,... 

    Zeolite-based catalytic micromotors for enhanced biological and chemical water remediation

    , Article New Journal of Chemistry ; Volume 44, Issue 44 , 2020 , Pages 19212-19219 Abedini, F ; Madaah Hosseini, H. R ; Sharif University of Technology
    Royal Society of Chemistry  2020
    Abstract
    Zeolite-based micromotors were developed to eliminate the biological and chemical contamination of water in a fast and efficient way. The motors consist of a silver-exchanged zeolite core and a partial catalytic coating. These porous engines showed rapid killing of Pseudomonas aeruginosa bacteria cells in a very short time, less than 7.5 minutes. The heavy metal uptake of the zeolitic motors during the first 20 minutes of contact was considerably higher than that of zeolite particles by 23% for Pb2+, 19% for Co2+, and 16% for Ni2+. Also, the maximum removal efficiency of the motors (at room temperature and for 6 hours) for Pb2+, Co2+, and Ni2+ was 93%, 87%, and 78%, respectively, higher than... 

    Molecular machinery responsible for graphene oxide's distinct inhibitory effects toward pseudomonas aeruginosa and staphylococcus aureus pathogens

    , Article ACS Applied Bio Materials ; Volume 4, Issue 1 , 2021 , Pages 660-668 ; 25766422 (ISSN) Ashari Astani, N ; Najafi, F ; Maghsoumi, A ; Huma, K ; Azimi, L ; Karimi, A ; Ejtehadi, M. R ; Gumbart, J. C ; Naseri, N ; Sharif University of Technology
    American Chemical Society  2021
    Abstract
    Graphene oxide flakes are considered as potential inhibitors for different pathogenic bacteria. However, the efficacy of inhibition changes for different types and strains of bacteria. In this work, we examine Pseudomonas aeruginosa and Staphylococcus aureus, two common hospital-acquired infections, which react quite differently to graphene oxide flakes. The minimum inhibitory tests yield two distinct outcomes: stopped proliferation for S. aureus versus almost no effect for P. aeruginosa. Integrating our experimental evidence with molecular dynamics simulations, we elucidate the molecular machinery involved, explaining the behavior we see in scanning electron microscopy images. According to... 

    MIL-125-based nanocarrier decorated with Palladium complex for targeted drug delivery

    , Article Scientific Reports ; Volume 12, Issue 1 , 2022 ; 20452322 (ISSN) Bagherzadeh, M ; Safarkhani, M ; Kiani, M ; Radmanesh, F ; Daneshgar, H ; Ghadiri, A. M ; Taghavimandi, F ; Fatahi, Y ; Safari-Alighiarloo, N ; Ahmadi, S ; Rabiee, N ; Sharif University of Technology
    Nature Research  2022
    Abstract
    The aim of this work was to provide a novel approach to designing and synthesizing a nanocomposite with significant biocompatibility, biodegradability, and stability in biological microenvironments. Hence, the porous ultra-low-density materials, metal–organic frameworks (MOFs), have been considered and the MIL-125(Ti) has been chosen due to its distinctive characteristics such as great biocompatibility and good biodegradability immobilized on the surface of the reduced graphene oxide (rGO). Based on the results, the presence of transition metal complexes next to the drug not only can reinforce the stability of the drug on the structure by preparing π–π interaction between ligands and the... 

    Niosome-encapsulated tobramycin reduced antibiotic resistance and enhanced antibacterial activity against multidrug-resistant clinical strains of Pseudomonas aeruginosa

    , Article Journal of Biomedical Materials Research - Part A ; Volume 109, Issue 6 , 2021 , Pages 966-980 ; 15493296 (ISSN) Hedayati Ch, M ; Abolhassani Targhi, A ; Shamsi, F ; Heidari, F ; Salehi Moghadam, Z ; Mirzaie, A ; Behdad, R ; Moghtaderi, M ; Akbarzadeh, I ; Sharif University of Technology
    John Wiley and Sons Inc  2021
    Abstract
    In the current study, niosome-encapsulated tobramycin based on Span 60 and Tween 60 was synthesized and its biological efficacies including anti-bacterial, anti-efflux, and anti-biofilm activities were investigated against multidrug resistant (MDR) clinical strains of Pseudomonas aeruginosa. The niosomal formulations were characterized using scanning electron microscopy, transmission electron microscopy, and dynamic light scattering measurement. The encapsulation efficiency was found to be 69.54% ±; 0.67. The prepared niosomal formulations had a high storage stability to 60 days with small changes in size and drug entrapment, which indicates that it is a suitable candidate for pharmaceutical... 

    Evaluation of a recycling bioreactor for biosurfactant production by Pseudomonas aeruginosa MR01 using soybean oil waste

    , Article Journal of Chemical Technology and Biotechnology ; Volume 91, Issue 5 , 2016 , Pages 1368-1377 ; 02682575 (ISSN) Bagheri Lotfabad, T ; Ebadipour, N ; Roostaazad, R ; Sharif University of Technology
    John Wiley and Sons Ltd 
    Abstract
    This study deals with the large-scale production of biosurfactant from soybean oil soapstock by Pseudomonas aeruginosa MR01. The production of biosurfactant was carried out in a newly designed bioreactor equipped with recycling flow under three operational conditions. Kinetic studies were conducted at both shake flask and 5-L bioreactor scales during fermentation in a soapstock medium. Mathematical equations were developed to model the kinetic patterns at both scales. RESULT: Statistical analyses demonstrated the goodness of fit, with regression r-squared, R2, between 0.97and 0.99 for different models. Furthermore, biosurfactant concentration in the bioreactor including the recycling flow,... 

    Experimental investigation on asphaltene biodegradability using microorganism: cell surface properties’ approach

    , Article Journal of Petroleum Exploration and Production Technology ; 2018 ; 21900558 (ISSN) Iraji, S ; Ayatollahi, S ; Sharif University of Technology
    Springer Verlag  2018
    Abstract
    Asphaltene precipitation is known to be responsible for serious challenges in oil industry such as wellbore damage, oil flow reduction, and plugging of transportation lines. The traditional methods to remove asphaltene deposition are mostly based on chemical solvent. One of the recent proposed green and cost–effect remedial methods is the application of microorganisms capable of consuming the heavy hydrocarbon chains. The cell surface hydrophobicity among others effectively manipulates the efficiency of the microorganism for asphaltene degradation. Besides, surface active agents would affect the microorganism adhesion and cell surface properties, and alters its hydrophobicity. Investigating... 

    Biodegradation of synthetic dye using partially purified and characterized laccase and its proposed mechanism

    , Article International Journal of Environmental Science and Technology ; Volume 16, Issue 12 , 2019 , Pages 7805-7816 ; 17351472 (ISSN) Ghobadi Nejad, Z ; Borghei, S. M ; Yaghmaei, S ; Sharif University of Technology
    Center for Environmental and Energy Research and Studies  2019
    Abstract
    The supernatant obtained from the extracellular laccase produced by Phanerochaete chrysosporium was used as the enzyme source to conduct a partial purification, characterization and dye decolorization study. The partially purified enzyme was stable in the pH range of 3–5 and showed an optimum activity at pH 4.0, using guaiacol as a substrate. Laccase stability of pH was determined and discovered to retain 100% of its activity at a pH of 4.0 after 2 h. The maximum enzyme activity was obtained between 30 and 50 °C. The maximum velocity and Michaelis constant were calculated as 3.171 µM−1·min and 1628.23 µM, respectively. The enzyme was activated by Fe2+, Zn2+, Ca2+ and Cu2+, while Hg2+, Mn2+,... 

    Experimental investigation on asphaltene biodegradability using microorganism: cell surface properties’ approach

    , Article Journal of Petroleum Exploration and Production Technology ; Volume 9, Issue 2 , 2019 , Pages 1413-1422 ; 21900558 (ISSN) Iraji, S ; Ayatollahi, S ; Sharif University of Technology
    Springer Verlag  2019
    Abstract
    Asphaltene precipitation is known to be responsible for serious challenges in oil industry such as wellbore damage, oil flow reduction, and plugging of transportation lines. The traditional methods to remove asphaltene deposition are mostly based on chemical solvent. One of the recent proposed green and cost–effect remedial methods is the application of microorganisms capable of consuming the heavy hydrocarbon chains. The cell surface hydrophobicity among others effectively manipulates the efficiency of the microorganism for asphaltene degradation. Besides, surface active agents would affect the microorganism adhesion and cell surface properties, and alters its hydrophobicity. Investigating... 

    Niosome-encapsulated tobramycin reduced antibiotic resistance and enhanced antibacterial activity against multidrug-resistant clinical strains of Pseudomonas aeruginosa

    , Article Journal of Biomedical Materials Research - Part A ; 2020 Hedayati Ch, M ; Abolhassani Targhi, A ; Shamsi, F ; Heidari, F ; Salehi Moghadam, Z ; Mirzaie, A ; Behdad, R ; Moghtaderi, M ; Akbarzadeh, I ; Sharif University of Technology
    John Wiley and Sons Inc  2020
    Abstract
    In the current study, niosome-encapsulated tobramycin based on Span 60 and Tween 60 was synthesized and its biological efficacies including anti-bacterial, anti-efflux, and anti-biofilm activities were investigated against multidrug resistant (MDR) clinical strains of Pseudomonas aeruginosa. The niosomal formulations were characterized using scanning electron microscopy, transmission electron microscopy, and dynamic light scattering measurement. The encapsulation efficiency was found to be 69.54% ±; 0.67. The prepared niosomal formulations had a high storage stability to 60 days with small changes in size and drug entrapment, which indicates that it is a suitable candidate for pharmaceutical... 

    Optimization and characterization of tannic acid loaded niosomes for enhanced antibacterial and anti-biofilm activities

    , Article Advanced Powder Technology ; 2020 Heidari, F ; Akbarzadeh, I ; Nourouzian, D ; Mirzaie, A ; Bakhshandeh, H ; Sharif University of Technology
    Elsevier B.V  2020
    Abstract
    The purpose of this study was to prepare and characterize an optimized system of tannic acid-loaded niosomes as a potential carrier for antibacterial and anti-biofilm delivery. The niosomal formulation was optimized using response surface methodology (RSM). The effects of the molar ratio of surfactant to cholesterol, drug concentration, and molar ratio of Span 60 to Tween 60 on particle size and drug entrapment efficiency of the niosomal nanocarrier were studied. The optimized nanoparticles were characterized in terms of the morphology, in vitro release profile, and antibacterial properties. Moreover, Fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC)... 

    Fabrication and evaluation of chitosan/gelatin/PVA hydrogel incorporating honey for wound healing applications: An in vitro, in vivo study

    , Article International Journal of Pharmaceutics ; Volume 592 , 2021 ; 03785173 (ISSN) Shamloo, A ; Aghababaie, Z ; Afjoul, H ; Jami, M ; Bidgoli, M. R ; Vossoughi, M ; Ramazani, A ; Kamyabhesari, K ; Sharif University of Technology
    Elsevier B.V  2021
    Abstract
    In this study, physically cross-linked hydrogels were developed by freezing-thawing method while different concentrations of honey were included into the hydrogels for accelerated wound healing. The hydrogel was composed of chitosan, polyvinyl alcohol (PVA), and gelatin with the ratio of 2:1:1 (v/v), respectively. Further, the effect of honey concentrations on antibacterial properties, and cell behavior was investigated. In vivo studies, including wound healing mechanism using rat model and histological analysis of section tissue samples were performed. The results illustrated that the incorporation of honey in hydrogels increased the ultimate strain of hydrogels approximately two times,...