Vol 80, No 3 - Abstracts

JSCS Vol 80, No 3

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Whole issue - PDF 2,391 kB

J. Serb. Chem. Soc. 80 (3) 279–304 (2015)

UDC *Pseudomonas aeruginosa:577.115+547.441:661.185.000.57+66.0; JSCS–4716; doi: 10.2298/JSC140627096R; Review

REVIEW

Rhamnolipid biosurfactant from Pseudomonas aeruginosa – from discovery to application in contemporary technology

MILENA G. RIKALOVIĆ, MIROSLAV M. VRVIĆ and IVANKA M. KARADŽIĆ*

1Faculty of Chemistry, University of Belgrade, Studentski trg 12–16, Belgrad, Serbia

*Department of Chemistry, Faculty of Medicine, University of Belgrade, Visegradska 26, Belgrade, Serbia

(Received 27 June, revised 19 September, accepted 20 September 2014)

The rhamnolipids will most likely be the next generation of biosurfactants to reach the market. They should follow closely after alkyl polyglycosides, already established in the biosurfactants market, and sophorolipids, which can be found in several cleaning agents. However, the greatest numbers of recent publications and patents among glycolipid biosurfactants have been dedicated to rhamnolipids. Produced mainly by Pseudomonas aeruginosa, rhamnolipids are mixtures of different rhamnolipid congeners, which show physico-chemical properties that differ from those of single congeners, with the most abundant structure in the mixture having the largest impact on the overall characteristics of the total mixture. Characteristics of biodegradability, low toxicity, production from renewable sources and antimicrobial (particularly antifungal) activity together make rhamnolipid biosurfactants particularly promising for broad commercial application. Although to date, bioremediation has been the major topic filed for patents utilizing rhamnolipids, the increasing number of patents for applications in cosmetics, agronomy and food industries, formulation of cleaners and nanotechnology indicates their future implementation in these fields.

Keywords: rhamnolipids; Pseudomonas aeruginosa; methods; production; application.

Full Article - PDF 325 kB Available OnLine: 31. 10. 2014. Cited by

J. Serb. Chem. Soc. 80 (3) 305–313 (2015)

UDC 547.587.51+547.77+542.913:537.5–962:615.28–188; JSCS–4717; doi: 10.2298/JSC140021101A; Original scientific paper

Microwave-assisted synthesis of some new coumarin–pyrazoline hybrids and their antimicrobial activity

DONGAMANTI ASHOK, BOMMIDI VIJAYA LAKSHMI, SIDDA RAVI and ARRAM GANESH

Department of Chemistry, Osmania University, Hyderabad, India

(Received 21 June, revised 15 October, accepted 20 October 2014)

A series of pyrazolines were synthesized by Michael addition of chalcones with hydrazine hydrate in the presence of sodium acetate under conventional heating and microwave irradiation. The structures of the newly synthesized chalcones and pyrazolines were established based on IR, 1H- and 13C-NMR and mass spectral data. All the synthesized compounds were screened for their antimicrobial activity. Some of the compounds showed very good activity compared to standard drugs against all pathogenic bacteria and fungi.

Keywords: coumarin; chalcones; Michael addition; microwave irradiation; pyrazolines.

Full Article - PDF 167 kB Supplementary Material PDF 89 kB Available OnLine: 31. 04. 2014. Cited by

J. Serb. Chem. Soc. 80 (3) 315–327 (2015)

UDC *Salmonella enterica:547.587.51+547.21.024:579.86:616.34:615.282; JSCS–4718; doi: 10.2298/JSC140619085R; Original scientific paper

A small library of 4-(alkylamino)-3-nitrocoumarin derivatives with potent antimicrobial activity against gastrointestinal pathogens

NIKO S. RADULOVIĆ, ZORICA STOJANOVIĆ-RADIĆ*, PREDRAG STOJANOVIĆ**,***, NIKOLA STOJANOVIĆ**, VIDOSLAV DEKIĆ**** and BILJANA DEKIĆ****

Department of Chemistry, Faculty of Science and Mathematics, University of Niš, Višegradska 33, 18000 Niš, Serbia

*Department of Biology and Ecology, Faculty of Science and Mathematics, University of Niš, Višegradska 33, 18000 Niš, Serbia

**Faculty of Medicine, University of Niš, Zorana Đinđića 81, 18000 Niš, Serbia

***Institute For Public Health Niš, Center of Microbiology, 18000 Niš, Serbia

****Department of Chemistry, Faculty of Science and Mathematics, University of Priština, Lole Ribara 29, 38220 Kosovska Mitrovica, Serbia

(Received 19 June, revised 22 August, accepted 29 August 2014)

Due to the confirmed antimicrobial activity of both natural and synthetic coumarin derivatives, the present study was envisaged to provide further insight into the antimicrobial potential of coumarins through the screening of a designed library of nine 4-(alkylamino)-3-nitrocoumarins against a panel of 24 laboratory strains and resistant (isolates) bacterial and fungal pathogens. All compounds showed some degree of strain-selective activity that in some cases was very pronounced, reaching the value of 0.04 nmol mL-1 (i.e., 12 ng mL-1) for the minimal inhibitory concentration against Candida albicans. The observed activities were higher against Gram-negative strains, among which the most susceptible strain, among both ATCC strains and clinical isolates, was Salmonella enterica subsp. enterica serovar Enteritidis. These results indicate to a high potential of these coumarins as antimicrobials for the treatment of gastrointestinal and other infections caused by highly resistant microbial strains. Finally, a multivariate statistical analysis of the herein obtained and previous results on the antimicrobial activity of related selected coumarins was performed to allow an easier structure–activity discussion.

Keywords: 4-(alkylamino)coumarins; antimicrobial activity; Candida albicans; multivariate statistical analysis; Salmonella enterica.

Full Article - PDF 261 kB Supplementary Material PDF 86 kB Available OnLine: 04. 09. 2013. Cited by

J. Serb. Chem. Soc. 80 (3) 329–342 (2015)

UDC 547.233+546.763+546.121.13:534.1:531.121; JSCS–4719; doi: 10.2298/JSC030914105D; Original scientific paper

Derivation of a new set of force field parameters for ammine complexes of chromium(III) containing halogenido ligands: modeling of the trans-influence of halogenido ligands

IVANA DJORDJEVIĆ, SONJA GRUBIŠIĆ, MILOŠ MILČIĆ* and SVETOZAR NIKETIĆ

Center for Chemistry, ICTM, University of Belgrade, Njegoševa 12, 11001 Belgrade, Serbia

*Faculty of Chemistry, University of Belgrade, Studentski trg 16, 11001 Belgrade, Serbia

(Received 3 September, revised 26 October, accepted 27 October 2014)

An approach to model the trans-influence using partial atomic charges derived from the molecular electrostatic potential by means of the restrained electrostatic potential (RESP) fitting method is exemplified on a series of halogenido–ammine octahedral chromium(III) complexes. RESP charges incorporated in the present vibrationally optimized consistent force field account for second-order phenomena, improve the modeling and assignment of skeletal vibrations, and reproduce the trends in frequency shifts along the F, Cl, Br, I series. In addition, a supplementary statistical analysis is given for the Cr–halogen bonds in the crystal structures from the CSD.

Keywords: partial atomic charges; chromium(III) complexes; trans-influence; consistent force field; skeletal vibrations.

Full Article - PDF 178 kB Supplementary Material PDF 146 kB Available OnLine: 31. 10. 2014. Cited by

J. Serb. Chem. Soc. 80 (3) 343–353 (2015)

UDC 547.466.1+539.16:547.466+532.74; JSCS–4720; doi: 10.2298/JSC140604069T; Original scientific paper

A quantitative structure–activity relationship (QSAR) study of peptide drugs based on a new descriptor of amino acids

JIAN-BO TONG, JIA CHANG, SHU-LING LIU and MIN BAI

Shaanxi University of Science and Technology, Xi’an 710021, China

(Received 4 June, accepted 7 July 2014)

The quantitative structure–activity relationship (QSAR) approach is used for finding the relationships between molecular structures and the activity of peptide drugs. In this work, the stepwise multiple regression method was employed to select the optimal subset of descriptors that have significant contributions to the drug activity of 21 oxytocin analogues, 48 bitter tasting threshold activities and 58 angiotensin-converting enzyme inhibitors. A new set of descriptor, SVWGM, was used for the prediction of the activity of the peptide drugs and then were used to build a model by the partial least squares method, The stability and generalization ability of the model was strictly analyzed by both internal and external validations, by cross-validation and external validation correlations.

Keywords: amino acids; peptide; quantitative structure–activity relationships; partial least square; SVWGM.

Full Article - PDF 305 kB Supplementary Material PDF 311 kB Available OnLine: 10. 07. 2014. Cited by

J. Serb. Chem. Soc. 80 (3) 355–366 (2015)

UDC 547.213+547.313.3–31:66.094.258:661.183.8+544.478; JSCS–4721, doi: 10.2298/JSC140505067Z; Original scientific paper

Higher propene yield by tailoring operating conditions of propane oxidative dehydrogenation over V₂O₅/g-Al₂O₃

YOUSEF ZAYNALI AND SEYED MEHDI ALAVI

Chemical Engineering Department, Iran University of Science and Technology, P. O. Box 16765-163, Tehran, Iran

(Received 5 May, revised 25 June, accepted 27 June 2014)

Supported vanadia catalysts were successfully synthesized using wet impregnation of g-alumina to study propane oxidative dehydrogenation (POD). The prepared catalysts were characterized by X-ray diffraction analysis, specific surface area determination, and temperature programmed reduction tests. Over a broad temperature range (340 to 630 °C), the effects of vanadia loading (2.7, 5.4, and 9 wt. %) and propane to oxygen ratio (3:1 to 1:3) were thoroughly investigated on propane conversion as well as propene yield at atmospheric pressure. The results indicated that on increasing the vanadia content, the activity of catalyst increased while the selectivity to propene decreased monotonically. With increasing temperature from 340 to 630°C, the yield to propene showed an ascending behavior for all catalyst samples. The yield to propene exhibited a maximum on changing the propane to oxygen ratio from 3:1 to 1:3. The yield increased with increasing oxygen partial pressure in the feed until an equimolar ratio of propane and oxygen and then it declined with further increase in the oxygen partial pressure. A maximum propene yield of 17 % was experienced on the catalyst with 2.7 wt. % vanadia at a temperature of 550 °C.

Keyword: propane oxidative dehydrogenation; vanadia loading; propane to oxygen ratio; feed composition.

Full Article - PDF 214 kB Available OnLine: 27. 06. 2014. Cited by

J. Serb. Chem. Soc. 80 (3) 367–376 (2015)

UDC 546.723–138.001:539.24+537.621:535.4–34; JSCS–4722; doi:10.2298/JSC140313053A; Original scientific paper

Wet milling versus co-precipitation in magnetite ferrofluid preparation

LÁSZLÓ ALMÁSY, DORINA CREANGA*, CLAUDIA NADEJDE*, LÁSZLÓ ROSTA, EKATERINA POMJAKUSHINA** and MANUELA URSACHE-OPRISAN*

Wigner Research Centre for Physics, P. O. Box 49, Budapest – 1525, Hungary

*Faculty of Physics, “Al. I. Cuza” University, 11A Carol I Bd., RO-700506, Iasi, Romania

**Laboratory for Development and Methods, PSI, CH-5232 Villigen, Switzerland

(Received 13 March 2014, accepted 21 May 2014)

Various uses of ferrofluids for technical applications continuously raise interest in the improvement and optimization of the preparation methods. This paper deals with the preparation of finely granulated magnetite particles coated with oleic acid in hydrocarbon suspensions following either chemical co-precipitation from iron salt precursors or wet milling of micron size magnetite powder with the goal to compare the benefits and disadvantages of each method. Microstructural measurements showed that both methods gave similar-sized magnetite particles of 10–15 nm. The wet-milled magnetite suspension had a higher saturation magnetization than that obtained in the relatively rapid co-precipitation synthesis. The different efficacies of ferrophase incorporation into kerosene could be related to the different mechanisms of oleic acid bonding to the surface of the nanoparticles. Comparative data showed that wet milling represents a viable alternative to the traditional co-precipitation method since despite of longer processing time, the impact of chemicals on the environment and remnant water in the final product could be avoided.

Keywords: magnetite nanoparticles; kerosene suspensions; X-ray diffraction; TEM; magnetometry; IR spectra.

Full Article - PDF 260 kB Supplementary Material PDF 88 kB Available OnLine: 21. 05. 2014. Cited by

J. Serb. Chem. Soc. 80 (3) 377–389 (2015)

UDC 662.75+662.61+66.023+544.4; JSCS–4723; doi: 10.2298/JSC140130029N; Original scientific paper

Euler–Euler granular flow model of the combustion of liquid fuels in a fluidized reactor

STEVAN NEMODA, MILICA MLADENOVIĆ, MILIJANA PAPRIKA, DRAGOLJUB DAKIĆ*, ALEKSANDAR ERIĆ and MIRKO KOMATINA**

”Vinča” Institute of Nuclear Sciences, University of Belgrade, Belgrade, Serbia

*Innovation Center, Faculty of Mechanical Engineering, University of Belgrade, Belgrade, Serbia

**Faculty of Mechanical Engineering, University of Belgrade, Belgrade, Serbia

(Received 30 January, revised and accepted 27 March 2014)

This paper deals with the numerical simulation of liquid fuel combustion in a fluidized reactor using two-fluid Eulerian–Eulerian fluidized bed modeling incorporating the kinetic theory of granular flow (KTGF) to gas and solid phase flow prediction. The comprehensive model of the complex processes in a fluidized combustion chamber incorporates, besides the prediction of gas and particular phase velocity fields, the energy equations for the gas and solid phase and the transport equations of conservation of chemical species with the source terms due to the conversion of chemical components. Numerical experiments showed that the coefficients in the model of inter-phase interaction drag force have a significant effect, and they have to be adjusted for each regime of fluidization. A series of numerical experiments was performed with combustion of liquid fuels in a fluidized bed (FB), with and without significant water content. The given estimations were related to the unsteady state, and the modeled period corresponds to the passing time of the flow through the reactor column. The numerical experiments were conducted to examine the impact of the water content in a liquid fuel on the global FB combustion kinetics.

Keywords: computational fluid dynamics model; combustion; fluidized bed; two-fluid model; non-conventional fuel.

Full Article - PDF 2,089 kB Supplementary Material PDF 88 kB Available OnLine: 27. 03. 2014. Cited by

J. Serb. Chem. Soc. 80 (3) 391–405 (2015)

UDC 622–034.3+54.05+66.061:621.928.17+622’17(497.11); JSCS–4724; doi: 10.2298/JSC140411097S; Original scientific paper

Bioleaching of copper from samples of old flotation tailings (Copper Mine Bor, Serbia)

SRĐAN STANKOVIĆ, IVANA MORIĆ*, ALEKSANDAR PAVIĆ*, SANDRA VOJNOVIĆ*, BRANKA VASILJEVIĆ* AND VLADICA CVETKOVIĆ

1Faculty of Mining and Geology, University of Belgrade, Đušina 7, Belgrade, Serbia and 2Institute for Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444a, Belgrade, Serbia

(Received 11 April, revised 4 July, accepted 23 September 2014)

Bioleaching of samples taken from depths of 10, 15, and 20 m from old flotation tailings of the Copper Mine Bor was conducted in shaken flasks using the extremely acidic water of Lake Robule as lixiviant. The yields of copper after five weeks of the bioleaching experiments were 68.34±1.21 % for the 15-m sample, 72.57±0.57 % for the 20-m sample and 97.78±5.50 % for the 10-m sample. The obtained results were compared to the results of acid leaching of the same samples and it was concluded that bioleaching was generally more efficient for the treatment of samples taken from depths of 10 and 20 m. The content of pyrite in the 20-m sample, which contained the highest amount of this mineral, was reduced after bioleaching. The benefits of this approach are recovery of substantial amounts of copper, reducing the environmental impact of flotation tailings and the application of abundant and free water from the acidic Robule Lake as lixiviant. The obtained results showed that bioleaching could be more efficient than acid leaching for copper extraction from flotation tailings with higher sulfide contents.

Keywords: bioleaching; flotation tailings; Lake Robule; Bor.

Full Article - PDF 687 kB Available OnLine: 20. 09. 2014. Cited by

J. Serb. Chem. Soc. 80 (3) 407–419 (2015)

UDC 582.26+66.081.000.57:669.24/.26+669.3/.5+661.183.2:544.4; JSCS–4725; doi: 10.2298/JSC140321060P; Original scientific paper

Biosorption characteristics of Spirulina and Chlorella cells for the accumulation of heavy metals

ANIKÓ KŐNIG-PÉTER*, FERENC KILÁR*^,**^,***, ATTILA FELINGER**^,*** AND TÍMEA PERNYESZI**^,***

*University of Pécs, Faculty of Medicine, Institute of Bioanalysis, Szigeti út 12, H-7624 Pécs, Hungary

**University of Pécs, Faculty of Science, Department of Analytical and Environmental Chemistry Ifjúság útja 6, H-7624 Pécs, Hungary

***University of Pécs, Analytical Chemistry and Geoanalytical Research Group, Szentágothai Research Center, Ifjúság útja 20, H-7624 Pécs, Hungary

(Received 21 March, revised 28 May 2014, accepted 2 June 2014)

The biosorption of heavy metals by dried Chlorella vulgaris and Spirulina platensis–Spirulina maxima cells was studied under various experimental conditions. The effects of biosorbent dosage, pH, adsorption time, temperature, initial metal concentration on the biosorption were examined. A biosorption process can be divided into two parts: the first part follows zero-order and the second part pseudo second-order kinetics. Characterization of biosorption equilibrium was evaluated employing the Langmuir and Dubinin–Radushkevich models using non-linear regression. The optimum pH range was found to be 5.0−6.0 for Pb(II) and 4.0−6.0 for Cu(II) and Cd(II) adsorption. Based on the experimental data, the maximum adsorption capacities for Pb(II), Cd(II) and Cu(II) were 144, 161 and 138 mg g-1 by Chlorella cells and 370, 201 and 165 mg g-1 by Spirulina cells. The corresponding values for activated carbon were 86, 134 and 43 mg g-1, respectively.

Keywords: algae; kinetics; isotherm; Langmuir; Dubinin–Radushkevich; activated carbon.

Full Article - PDF 652 kB Available OnLine: 05. 06. 2014. Cited by

J. Serb. Chem. Soc. 80 (3) 421–433 (2015)

UDC 547.211:66.011:510.644:519.233.5; JSCS–4726; doi: 10.2298/JSC020414110S; Original scientific paper

Modeling of methane emissions using the artificial neural network approach

LIDIJA J. STAMENKOVIĆ, DAVOR Z. ANTANASIJEVIĆ*, MIRJANA Đ. RISTIĆ, ALEKSANDRA A. PERIĆ-GRUJIĆ and VIKTOR V. POCAJT

University of Belgrade, Faculty of Technology and Metallurgy, Karnegijeva 4, 11120 Belgrade, Serbia

*University of Belgrade, Innovation Center of the Faculty of Technology and Metallurgy, Karnegijeva 4, 11120 Belgrade, Serbia

(Received 2 April, revised 26 August, accepted 7 November 2014)

The aim of this study was to develop a model for forecasting CH4 emissions at the national level, using artificial neural networks (ANN) with broadly available sustainability, economical and industrial indicators as their inputs. ANN modeling was performed using two different types of architecture; a backpropagation neural network (BPNN) and a general regression neural network (GRNN). A conventional multiple linear regression (MLR) model was also developed in order to compare the model performance and assess which model provides the best results. ANN and MLR models were developed and tested using the same annual data for 20 European countries. The ANN model demonstrated very good performance, significantly better than the MLR model. It was shown that a forecast of CH4 emissions at the national level using the ANN model could be made successfully and accurately for a future period of up to two years, thereby opening the possibility to apply such a modeling technique, which could be used to support the implementation of sustainable development strategies and environmental management policies.

Keywords: national emission; general regression neural network; backpropagation neural network; multiple linear regression.

Full Article - PDF 215 kB Supplementary Material PDF 66 kB Available OnLine: 20. 09. 2014. Cited by

J. Serb. Chem. Soc. 80 (3) 435–452 (2015)

UDC 371.124:54+011.892+373.5; JSCS–4727; doi: 10.2298/JSC1401002121T; Original scientific paper

Chemistry curricular knowledge of secondary school teachers

BILJANA TOMAŠEVIĆ and DRAGICA TRIVIĆ

Faculty of Chemistry, University of Belgrade, P. O. Box 158, 11001 Belgrade, Serbia

(Received 2 October, revised 7 December 2014, accepted 8 December 2014)

In the course of this research, the extent of chemistry teachers’ professional knowledge related to the structure, contents and application of chemistry curricula and their components was investigated. The research comprised 119 teachers from 69 secondary schools (25 grammar schools and 44 vocational secondary schools). The questions in the questionnaire referred to general curriculum knowledge, knowledge of chemistry curriculum and the views/assessments of the teachers concerning the necessary changes in the curricula currently in effect. The teachers’ answers showed that the most important components of the curriculum for their work are the goals and operative tasks/outcomes. The results indicated that information in the curriculum components exits that remains unused although it is relevant for a certain level of planning. Among the teachers in the sample, higher percentages of those with an appropriate teachers’ training programme applied information from the curriculum within the teaching process through demonstration methods and problem solving. The research that was conducted provides a basis for defining the indicators for monitoring the level of teachers’ capability to apply curricular knowledge in their practice. Such indicators are important for creating teaching situations and teachers’ activities within the framework of initial education and continuing professional development of teachers.

Keywords: curricular knowledge; curricular components; annual work plan; monthly work plan; lesson plan; chemistry teaching.

Full Article - PDF 310 kB Supplementary Material PDF 62 kB Available OnLine: 13. 12. 2014. Cited by

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