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THE ROLE OF SIALIC ACID IN NATURAL MUD IN THE GROWTH AND NEURAMINIDASE SECRETION OF VIBRIO CHOLERAE non-O1 STRAINS
I. Abrashev, P. Petrov, R. Eneva
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(PDF 103k)

Abstract: The growth rate and multiplication of Vibrio cholerae non-O1 strain in the mud from the Pomorie lake (near the Black sea) were studied. The neuraminidase enzyme secretion and its accumulation at different growth phases and different cultivation temperatures were studied too. The obtained results demonstrate that the mud from the Pomorie lake is a good vibrio growth medium and substrate for the neuraminidase enzyme secretion. The role of the neuraminidase enzyme in the metabolism of mucins and glycoproteins on trophic level was confirmed.

AN INVESTIGATION ON PESTICIDE ENCAPSULATION IN BINDING COMPONENTS
N. Dimova, S. Petrov
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(PDF 80k)

Abstract: The encapsulation of the pesticides Perozin E and Ridomil Gold was studied and their content in aqueous emissions was determined during the storage of the capsules obtained. The epoxy resins “Epoxal II” and “Versamid” and cement were used as binders. Capsules containing 5, 10, 15 and 20 g Perozin E and Ridomil Gold in epoxy resins, and 2, 4, 6, 8 and 10 g pesticides in cement were prepared. The capsules were kept in water and the emissions of pesticides were periodically analyzed by HPLC. The results showed that the emission levels from epoxy capsules were low enough in the aqueous phase and reached 2.5-3.3 mg l^-1. The emission levels from cement capsules were quite higher (up to 15 mg l^-1) and concentration equilibrium was not observed for the whole period of the investigation.

web-BASED monitoring of THE fires In THE Balkans USING satellite data during July and August 2007
R. Nedkov, M. Dimitrova, M. Zaharinova, I. Ivanova
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(PDF 2652k)

Abstract: A space data-based monitoring of the massive forest and agrarian fires which sprang up in the Balkans in 2007 are presented. This monitoring has been performed by the Aerospace Information Center of the Space Research Institute at the Bulgarian Academy of Sciences since the summer of 2007. On the basis of satellite and GPS data, it is shown how to perform the localisation of the fire zones as well as to estimate the consequences from the fires. The fires sprung up in July 2007 around Stara Zagora and Topolovgrad were observed. Тhe results of the satellite monitoring of the fires which took place in Macedonia and the Peloponnesian peninsula of Greece are shown too.

ANAEROBIC DIGESTION OF WASTE FRUITS AND VEGETABLES (A REVIEW)
B. Koumanova, M. Saev
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(PDF 103k)

Abstract. Every day large quantities of fruits and vegetables from markets and shops are converted into wastes. A conventional method for their removal is the deposition into landfills. The high organic content is a reason to develop different methods for their utilisation. Anaerobic digestion is a suitable method resulting in biogas production as well as a solid phase enriched in nutrients. A literature survey on this problem has been done. The experimental conditions, the content of the fruit and vegetable wastes used and the biogas yield have been compared.

BIODEGRADATION OF RICE MILL EFFLUENT BY IMMOBILISED PSEUDOMONAS SP. CELLS
R. Manogari , D. Daniel , A. Krastanov
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(PDF 78k)

Abstract: Rice milling is the process of removing the husk and part of the bran from paddy in order to produce edible rice. Rice production, especially parboiled rice production, generally requires a large amount of water for soaking the paddy. This water, if not properly treated, could give rise to water pollution. The limitations in the physico-chemical methods make the biological methods favourable alternatives for the removal of pollutants from the industrial effluents. A bacterial strain was isolated and identified as Pseudomonas sp. through morphological and biochemical tests. Preliminary experiments with Pseudomonas sp. were carried out, using free and immobilised cells. Experiments in a packed bed system using immobilised cells indicated a 86.44 % reduction in the COD and a 55.34 % reduction in the BOD after 24 hours. The electrical conductivity, salinity and total dissolved solids were found to decrease to a considerable extent. Studies with varying cell loading showed that a cell loading of 1.7 – 2.2 mg cells per bead was capable of improving the quality of the rice mill effluent successfully.

THE CONVERGENCE OF BIOTECHNOLOGY AND NANOTECHNOLOGY AS AN ACCELERATOR OF THE DEVELOPMENT OF BIOFILM TECHNOLOGIES
L. Nikolov, V. Mamatarkova, S. Slavchev, S. Stoychev
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(PDF 262k)

Abstract. Аn attempt is made to elucidate some of the existing potentialities offering the convergence of the biotechnology and nanotechnology in biofilm science and technology. This is achieved by submitting information about the main features of the biofilm structures. The current terminology for biotechnology and nanotechnology is also specified and some new notions have been introduced. Using the terminology and presenting in dynamics the formation and functioning of biofilms, the main reason for their qualification as complex systems in terms of the system approach is presented. Special attention is paid as well to the self- organization of biofilms and to the possible intervention into it. On this basis, some of the main points of the convergence of biotechnology and nanotechnology are revealed and the future developments are discussed. The notions of “nanobiotechnology” and “bionanotechnology” are discussed as appropriate expressions reflecting the convergence of these two modern fields of R&D activity in biofilm technologies.

MICROBIAL PURIFICATION OF WASTE BIODEGRADATION LIQUID PRODUCTS
V. Ilyin, D. Korshunov, N. Chuvilskaya, G. Doronina, R. Mardanov, L. Moukhamedieva, N. Novikova, L. Starkova, E. Deshevaya
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(PDF 96k)

Abstract. The problem of waste utilisation is very acute in view of a piloted spaceflight to Mars. A peculiarity of the life support on piloted spaceships is that there is no shower on board, therefore wipes and towels are the most common means for hygiene procedures and, therefore, they form the largest waste mass. The other potentially expected kinds of wastes are the non-edible residuals of greenhouse plants. Previous investigations considered these kinds of wastes to be well degradable. However, the liquid products of the biodegradation contain much soluble organics which are not suitable for straight admission to the water supply system. These liquid products of the biodegradation were purified with the aid of aerobic microbial associations. The purification was satisfactory, especially for plant wastes.

MONITORING AND CONTROL OF ATMOSPHERIC GAS COMPOSITION IN SPACE PLANT GROWTH FACILITIES: SELECTION OF CO₂ SENSORS FOR THE SVET-3 SPACE GREENHOUSE
S. Sapunova, T. Ivanova, P. Kostov, Y. Naydenov, I. Ilieva, I. Dandolov
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(PDF 328k)

Abstract. A main motivation and final goal of all plant space investigations has always been to create advanced Biological Life Support Systems where plants have an essential role in keeping and supporting the astronauts’ life. Small plant growth facilities with various levels of automation and control have been developed and flown on board the Russian Space Station MIR, the U.S. Space Shuttle and the International Space Station. The paper presents a survey of the atmospheric gas composition control systems used in these facilities. The objectives and first steps of the research work on developing a new generation of space greenhouse - SVET-3, are described, focusing on the channel for plant environment measurements. Considerations taken into account in the selection of CO₂ sensors are listed. Comparative assessment of the technical characteristics of CO₂ sensors is made to choose those that best meet the requirements.

MIMO VARIABLE STRUCTURE CONTROL OF A WASTEWATER TREATMENT PROCESS
K. Dahech, T. Damak, A. Toumi
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(PDF 203k)

Abstract: In this paper, we consider the control problem of a nonlinear system which is considered as a denitrification process used for the biological treatment of wastewater. The bioreactor to be controlled is a nonlinear and time-varying system, which therefore needs a robust state feedback. The variable structure control theory can be useful for this situation when model uncertainties, parameter variations and disturbances occur. The main contribution of this paper consists in designing a multi-input/multi-output (MIMO) variable structure control of the denitrification process. Two approaches are developed: classical and generalised variable structure control. The performances of the two approaches are compared and illustrated by means of simulations.

BIOFUEL CELLS: STATE OF THE ART AND PERSPECTIVES
K. Penev, V. Pupkevich, B. Bagchehsaraee, N. Grawburg and D. Karamanev
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(PDF 91k)

Abstract. On the basis of a comprehensive explanation of the principles of biofuel cells functioning, a review of the state of the art in this field is presented. Some of the most important achievements in developing the main elements of these new devices are described. The main biofuel cell peculiarities are presented. The crucial role of the biocatalysts is discussed. The types of cathodes and of anodes as well as of solid membranes are critically scrutinised. In this connection, the most important technological problems and their possible solving are discussed. The potentialities of implementating such devices in waste water treatment are assessed. The results of the research show that the biofuel cells can generate electricity from waste waters and other organic materials. However, the power density is still low for practical applications. The main goal of future R&D activity should be concentrated on a significant improvement of this parameter.

CONTENTS

Editor's comment

I. Simeonov 3

I. Human and Biosphere

Web-based monitoring of the fires in the Balkans using satellite data during July and August 2007

R. Nedkov, M. Dimitrova, M. Zaharinova, I. Ivanova 13

Biofuel cells: state of the art and perspectives