DEPARTMENT OF EXTREMOPHILIC BACTERIA
Head: Associate Professor Margarita Kambourova, PhD
Tel: +359 2 979
e-mail: margikam@microbio.bas.bg
1958
1981
1986
1986
1996-1997
Born July 22, 1958, Sofia
Diploma, Faculty of Biology, Sofia State University
PhD in Micribiology, Institute of Microbiology, BAS
Research Scientist, Institute of Microbiology
The Royal Society Postdoctoral fellow, Department of Biological Sciences, Heriot-Watt
University, Edinburgh, UK
2001
DFG Postdoctoral fellow, Technische Microbiologie, Technische Universitat, Hamburg,
Germany
2002
DFG Postdoctoral fellow, Technische Microbiologie, Technische Universitat, Hamburg,
Germany
Associated Professor. Institute of Microbiology, BAS
Head of Department of Extremophilic Bacteria, Institute of Microbiology, BAS
NATO fellow,Institute of Protein Biochemistry, CNR, Naples, Italy
2003
2004
2004
Teaching
Since 1996
Faculty of Information Technologies, Specialty Bioinformatics, Sofia University
STAFF
Alexandra Tonkova, PhD, Associate Professor
Anna Derekova, PhD, Research Scientist
Ivanka Bojadzhieva, PhD, Research Scientist
Iva Tomova, PhD, Research Scientist
Nadja Kirilova, MS, Research Assistant
Nikolina Atanasova, MS, Research Assistant
Tzvetina Kitayska, MS, Research Assistant
Iva Ivanova, MS, Research Assistant
Main Reserch Topics
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Biodiversity of extremophilic bacteria. The application of the molecular
approach for characterization of the biodiversity in microbial communities
has lead to basic changes in our opinion about the extent of our knowledge
on the organism world. Bulgaria is rich in thermal springs, representing the
natural ecosystem for thermophilic microorganisms. New, cultivationindependent methodologies as well as classical microbiological and
biochemical approaches are used for searching of unknown
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microorganisms which could hardly be assigned to the same phylogenetic
units with the previously isolated by cultivation techniques organisms.
Biosynthetic capacity of extremophilic microorganisms to synthesize
biotechnologically valuable enzymes. These organisms have been
identified as industrially important due to the production of thermostable
enzymes. Regulation of enzyme synthesis is investigated in batch and
continuous cultures. Producers of different hydrolases were isolated: αand β-amylases, cyclo dextrin gluacno transferase, glucosidase,
pullulanase, inulinase, pectinase, xylanase, lipase, protease, gellan-lyase
et al. Optimal schemes for purification of the enzymes with maximum yield
were created. Substrate specificities of enzymes, physico-chemical
parameters of action, kinetic constants of enzyme reactions, influence of
different inhibitors, detergents and organic solvents on enzyme activities
were investigated.
Biosynthesis of bacterial exopolysaccharides from thermophilic
bacteria. Synthesized by thermophilic bacteria exopolysaccharides
express unusual thermostability and could be successfully used as
viscosifiers and plastifiers in pharmaceutical industry and as gelling agents
in food industry. A polysaccharide with very high biological activity was
isiolated. It increased the lethal dose of avarol almost 20 fold.
Immobilization of synthesized enzymes and of cell-producers for their
more effective application as industrial biocatalysts. The cells were
immobilized by entrapment in different gels and hybrid nanomaterials or
attachment to membranes. Enzymes were immobilized by physical
absorption, cross-linking and ion-binding. The application of the
biocatalysts received in polycyclic and continuous processes proved the
effectiveness of immobilization.
Ongoing Projects
I.
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International projects
Advanced Fluorescence Sensors for Detection of Hazardous Agents. Project
supervisor: S. D’Auria (Italy), Project leader: M. Kambourova. NATO
Collaborative Linkage Grant N.CBP.EAP.CLG.9824372006-2008.
Purification, characterization and crystalogtaphic analysis of a thermostable
gellan lyase, synthesized by originally isolated thermophilic aerobic bacterial
strain. Project supervisor: Assoc. Prof. P. Hristova, Project leader: M.
Kambourova. Grant BG 16/2005. Joint research project between NFSR,
Bulgaria and Greece (2005-2008).
Production of exopolysaccharides from thermophilic bacteria, isolated from hot
springs in Bulgaria and Italy. Bilateral agreement between Bulg. Acad. Sci.
and CNR (2007-2009). Coordinator: Assoc. Prof . M. Kambourova
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Magnetic nano-materials for immobilization of bacterial cells and CGT-ase for
production of cyclodextrins. Bilateral agreement between Bulg. Acad. Sci. and
Czech Acad. Sci. P-43/20.11.2007 (2007-2009). Coordinator: Assoc. Prof . A.
Tonkova
II.
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Bulgarian projects
Isolation of alkalophilic bacilli from Bulgarian thermal springs and soils for
thermostable β-cyclodextrin glucanotransferase production. Project leader: A.
Tonkova. Grant B-1521/05, NFSR, Bulgaria (2005-2009).
Molecular characterization of phylogenetic diversity of the bacteria in hot
springs located in South-West Bulgaria by 16S rDNA analysis. Project leader:
M. Kambourova. Grant B 1511/05, NFSR, Bulgaria (2005-2009).
Regiospecific synthesis of structured lipids for food and medicine catalysed by
immobilized lipase from B. stearothermophilus MC7. Project supervisor: M.
Guncheva, Institute of Organic Chemistry, BAS; Project leader: A. Derekova,
MSc. Grant C-МU, NFSR 1501/05, Bulgaria (2005-2008).
Molecular characterization (by 16S rDNA) of phylogenetic diversity of the
microorganisms in Bulgarian hot springs in the region of Velingrad (Central
Bulgaria). Isolation of novel microbial enzymes with biotechnological
importance. Project leader: M. Kambourova. National Programme Genomics,
NSFR, Bulgaria (2005-2009).
Investigation of new hybrid nanomaterials for obtaining biocatalysts by
immobilized whole prokaryotic and eukaryotic microbial cells. Project leader:
Assoc. Prof. P. Aleksieva. Participant from the Department of Extremophilic
Bacteria: D-r L. Kabaivanova. National Programme Nanomaterials.
Magnetic nano-materials for immobilization of CGT-ase and production of
gama- and beta-cyclodextrins. Bilateral agreement between Bulg. Acad. Sci.
and Czech Acad. Sci. P-43/20.11.2007 (2007-2009). Coordinator: Assoc. Prof
. A. Tonkova.
Most Important Achievements
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A moderate thermophilic bacterial strain Bacillus sp. UG-5B with
benzonitrilase activity was isolated from polluted industrial waters. The
benzonitrile degradation was realized via nitrilase pathway. Due to the high
enzyme thermostability of free or immobilized cells as well as the broad
substrate specificity, the isolated strain, Bacillus sp. UG-5B could have a
potential application in chemical synthesis or various detoxification
processes.
An effective synthesis of cyclodextrin glucanotransferase was realized by
magnetic biocatalysts containing cells of Bacillus circulans ATCC 21783
and enzyme with a high specific activity was obtained.
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New obligate alkalophilic Bacillus strains were isolated from Bulgarian
habitats and successfully used for cyclodextrin glucanotransferase
production.
A new isolated bacterial strain representing novel species, Anoxybacillus
rupiensis, was isolated from Bulgarian hot spring.
The originally isolated from Bulgarian hot spring
Bacillus
stearothermophilus strain was described as the only producer of
thermostable gellan lyase reported up to now. Its thermostability
determines the possibility for running industrial processes at temperature
higher than 60°C in which temperature gellan is soluble.
Recent Publications
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Atanasova N., Petrova P., Ivanova V., Yankov D., Vassileva A., Tonkova A. (2008).
Isolation of novel alkaliphilic Bacillus strains for cyclodextrin glucanotransferase
production. Appl Biochem Biotech 149, 155-167.
Atanassova M., Derekova A., Mandeva R., Sjøholm C., Kambourova M. (2008).
Anoxybacllus bogrovensis sp. nov., a novel thermophilic bacterium isolated from Dolni
Bogrov’s hot spring, Bulgaria. Int. J. Syst. Evol. Microb. 58 (10), 2330 – 2335.
Chernev, G., Samuneva, B., Djambaski, P., Kabaivanova, L., Emanuilova, E., Miranda
Salvado I. M., Fernandes, M.H.V., Wu, A. (2007). Synthesis and structure of new
biomaterials containing chitosan. Physics and Chemistry of Glasses: European J. Glass
Sci Technol, B48/3, 147-150.
Chernev, G., Samuneva, B., Djambaski, P., Kabaivanova, L., Emanuilova, E., Miranda
Salvado, I.M., Wu, A. (2008). Synthesis and selected properties of silicate hybrids
containing sepharose Advanced Mater Res 39-40, 53-56.
Chernev, G., Samuneva, B., Djambaski, P., Kabaivanova, L., Emanuilova, E., Salvado,
I.M.M., Fernandes, M.H.V., Wu, A. (2008). Synthesis and structure of new biomaterials
containing silica and chitosan Phys Chem Glasses B 49 (1), 11-14,
Deckers D., Masschalck B., Aertsen A., Van Tiggelen C., Atanassova M., Michiels C.W.
(2004). Periplasmic Lysozyme Inhibitor Confers Lysozyme Resistance to Escherichia
coli. CMLS, Cell Mol Life Sci. 61, 1229 – 1237.
Deckers, D., Masschalck, B., Aertsen, A., Callewaert, L., Van Tiggelen, C., Atanassova,
M., Michiels, C.W. (2004). “Periplasmic Lysozyme Inhibitor Contributes to Lysozyme
Resistance in Escherichia coli. Cell Mol Life Sci, 61,. 1229 – 1237.
Derekova,
A.,
Sjøholm,
C.,
Mandeva,
R.,
Kambourova,
M.
(2007).
Anoxybacillus rupiensis sp. nov., a novel thermophilic bacterium isolated from Rupi
basin (Bulgaria). Extremophiles 11577-583.
Derekova, A., Mandeva, R., Kambourova M. (2008). Phylogenetic diversity of
thermophilic carbohydrate degrading bacilli from Bulgarian hot springs. World J.
Microbiol. Biotechnol. 24 (9), 1697-1702.
Derekova, A., Sjoholm, C., Mandeva, R., Michailova, L., Kambourova, M. (2006).
Biosynthesis of a thermostable gellan lyase by newly isolated and characterized strain of
Geobacillus stearothermophilus 98. Extremophiles, 10 (4), 321-326.
Groudieva, T., M. Kambourova, H. Yusef, M. Royter, R. Grote, H. Trinks, G. Antranikian.
(2004). Diversity and cold-active hydrolytic enzymes of culturable bacteria associated
with Arctic sea ice, Spitzbergen. Extremophiles 8, 475-488.
Guncheva, M., Zhiryakova, D., Radchenkova, N., Kambourova, M. (2008). Acidolysis of
Tripalmitin with Oleic Acid Catalyzed by a Newly Isolated Thermostable Lipase. J. Am.
Oil Chem. Soc., 85, 129-132.
Guncheva, M., Zhiryakova, D., Radchenkova, N., Kambourova, M. (2007). Effect of
nonionic detergents on the activity of a thermostable lipase from Bacillus
stearothermophilus MC7. J Mol. Catal B: Enzym 49 (1-4), 88-91.
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Guncheva, M., Zhiryakova, D., Radchenkova, N., Kambourova, M. (2009). Properties of
immobilized lipase from Bacillus stearothermophilus MC7. Acidolysis of triolein with
caprylic acid. World Journal of Microbiology and Biotechnology (in press).
Kabaivanova, L., Dobreva E., Emanuilova, E., Chernev, E., Samuneva, B., Salvado, I.
(2006). Synthesis, structure and application of new hybrid nanomaterials for cell
immobilization. Minerva Biotechnol, 18, 23-29.
Kabaivanova, L., Dobreva, E., Dimitrov, P., Emanuilova, E. (2005). Immobilization of
cells with nitrilase activity from a thermophilic bacterial strain. J Ind Microbiol Biotechnol
32, 7-11.
Kabaivanova, L., Emanuilova, E., Chernev, G., Samuneva, B., Djambaski, P., Miranda
Salvado I. M. (2007). Comparative study of two types of hybrid biocatalysts applied in a
biodegradation process. Minerva Biotechnol., 19, 57-63.
Kabaivanova, L., Emanuilova, E., Dimitrov, P., Engibarov, S., Boyadzhieva, I., Dobreva,
E. (2008). Nitrile degradation by free and immobilized cells of the thermophile Bacillus
sp. UG-5B, isolated from polluted industrial waters. World J. Microbiol. Biotechnol. 2,
2383–2388.
Kambourova, M., Mandeva, R., Fiume, I., Maurelli, L., Rossi, M., Morana, A. (2007).
Hydrolysis of xylan at high temperature by co-action of the xylanase from Anoxybacillus
flavithermus BC and the beta-xylosidase/alpha-arabinosidase from Sulfolobus
solfataricus Oalpha. J. Appl. Microbiol.. 102, 1586–1593.
Kambourova, M., Mandeva, R., Dimova, D., Poli, A., Nicolau,s B., Tommonaro G. (2009).
Production and characterization of a microbial glucan, synthesized by Geobacillus
tepidamans V264 isolated from Bulgarian hot spring. Carbohydrate Polymers, (in press).
L. Callewaert, B. Masschalck, D. Deckers, D. Nakimbugwe, M. Atanassova, A. Aertsen,
C. W. (2005). Michiels “Purification of Ivy, a lysozyme inhibitor from E. coli, and
characterization of its specificity for various lysozymes”. Enzyme Microb Tech, 2, 205 –
211.
Nakimbugwe, D., Masschalck B., Atanassova M., Zewdie-Bosüner, A., Michiels, C.W.
(2006). Comparison of bactericidal activity of six lysozymes at atmospheric pressure and
under high hydrostatic pressure. Int. J. Food Microbiol., 108, 355-363.
Nakimbugwe, D., Masschalck, B., Atanassova, M., Zewdie-Bosüner A., Michiels, C.W.
“Comparison of bactericidal activity of six lysozymes at atmospheric pressure and under
high hydrostatic pressure”. Int. J. Food Microbiol., No 108, pp. 355 – 363, 2006.
Safarikova M., Atanasova N., Ivanova V., Weyda F., Tonkova A. (2007). Cyclodextrin
glucanotransferase synthesis by semicontinuous cultivation of magnetic biocatalysts fron
cells of Bacillus circulans ATCC 21783. Process Biochem, 42, 1454-1459.
Samuneva, B., Djambaski, P., Kashchieva, E., Chernev, G., Kabaivanova, L.,
Emanuilova, E., Salvado, I.M.M., Fernandes M.H.V., Wu, A. (2007). Sol-gel synthesis
and structure of silica hybrid biomaterials . J. Non-Cryst. Solids, 354/2-9:733-740.
Samuneva, B., Djambaski, P., Kashchieva, E., Chernev, G., Kabaivanova, L.,
Emanuilova, E., Salvado, I.M.M., (...), Wu, A. (2008). Sol-gel synthesis and structure of
silica hybrid biomaterials J. Non-Cryst Solids 354 733-740.
Samuneva, B., Kabaivanova, L., Chernev, G., Djambaski, P., Kashchieva, E.,
Emanuilova, E., Miranda Salvado, I.M., (...), Wu, A. (2008). Sol-gel synthesis and
structure of silica hybrid materials J Sol-Gel Sci Techn 48, 73-79.
Vassileva A., Atanasova N., Ivanova V., Dhulster P., Tonkova A. (2007). Characterization
of cyclodextrin glucanotransferase from Bacillus circulans ATCC 21783 in terms of
cyclodextrin production. Ann Microbiol, 57 (4) 609-615.
Vassileva, A., Beschkov, V., Ivanova, V., Tonkova, A. (2005). Continuous cyclodextrin
glucanoransferase production by free and immobilized cells of Bacillus circulans ATCC
21783 in bioreactors. Process Biochem 40, 3290-3295.