The research activity of the Department of
Extremophilic Bactetria
The research activity of the Department of Extremophilic Bactetria is oriented to the next
scientific problems:
1. 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, cultivation-independent
methodologies as well as classical microbiological and biochemical approaches
are used for searching of unknown microorganisms which could hardly be
assigned to the same phylogenetic units with the previously isolated by
cultivation techniques organisms.
2. 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: α- and 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, physicochemical parameters of action, kinetic constants of enzyme reactions, influence of
different inhibitors, detergents and organic solvents on enzyme activities were
investigated.
3. 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.
4. 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.
Current projects:
I.
International projects
1. 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.
2. 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).
3. Production of exopolysaccharides from thermophilic bacteria, isolated from
hot springs in Bulgaria and Italy.
Bilateral agreement between Bulg. Acad. Sci. and CNR (20072009).
Coordinator: Assoc. Prof . M. Kambourova
4. 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.
Bulgarian projects
1. 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)
2. 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)
3. 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).
4. 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)
5. 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.
6. 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
Selected publications for last five years:
1. Atanasova N., Petrova P., Ivanova V., Yankov D., Vassileva A., Tonkova A.
Isolation of novel alkaliphilic Bacillus strains for cyclodextrin glucanotransferase
production. Appl Biochem Biotech 149, 155-167, 2008.
2. Atanassova M., Derekova A., Mandeva R., Sjøholm C., Kambourova M.
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, 2008.
3. Chernev, G., Samuneva, B., Djambaski, P., Kabaivanova, L., Emanuilova, E.,
Miranda Salvado I. M., Fernandes, M.H.V., Wu, A. Synthesis and structure of
new biomaterials containing chitosan. Physics and Chemistry of Glasses:
European J. Glass Sci Technol, B48/3, 147-150, 2007.
4. Chernev, G., Samuneva, B., Djambaski, P., Kabaivanova, L., Emanuilova, E.,
Miranda Salvado, I.M., Wu, A. Synthesis and selected properties of silicate
hybrids containing sepharose Advanced Mater Res 39-40, pp. 53-56, 2008.
5. Chernev, G., Samuneva, B., Djambaski, P., Kabaivanova, L., Emanuilova, E.,
Salvado, I.M.M., Fernandes, M.H.V., Wu, A. Synthesis and structure of new
biomaterials containing silica and chitosan Phys Chem Glasses B 49 (1), pp. 1114, 2008.
6. Deckers D., Masschalck B., Aertsen A., Van Tiggelen C., Atanassova M.,
Michiels C.W. Periplasmic Lysozyme Inhibitor Confers Lysozyme Resistance to
Escherichia coli. CMLS, Cell Mol Life Sci. Vol. 61 No 10, 1229 – 1237, 2004.
7. Deckers, D., Masschalck, B., Aertsen, A., Callewaert, L., Van Tiggelen, C.,
Atanassova, M., Michiels, C.W. “Periplasmic Lysozyme Inhibitor Contributes to
Lysozyme Resistance in Escherichia coli. Cell Mol Life Sci, Vol. 61, No 10, pp.
1229 – 1237, 2004.
8. Derekova, A., Sjøholm, C., Mandeva, R., Kambourova, M. Anoxybacillus
rupiensis sp. nov., a novel thermophilic bacterium isolated from Rupi basin
(Bulgaria). Extremophiles v. 11, No 4, 577-583, 2007.
9. Derekova, A., Mandeva, R., Kambourova M. Phylogenetic diversity of
thermophilic carbohydrate degrading bacilli from Bulgarian hot springs. World J.
Microbiol. Biotechnol. 24 (9), 1697-1702, 2008.
10. Derekova, A., Sjoholm, C., Mandeva, R., Michailova, L., Kambourova, M.
Biosynthesis of a thermostable gellan lyase by newly isolated and characterized
strain of Geobacillus stearothermophilus 98. Extremophiles, 10 (4), 321-326,
2006.
11. Groudieva, T., M. Kambourova, H. Yusef, M. Royter, R. Grote, H. Trinks, G.
Antranikian. Diversity and cold-active hydrolytic enzymes of culturable bacteria
associated with Arctic sea ice, Spitzbergen. Extremophiles v.8, No 6, 475-488, 2004.
12. Guncheva, M., Zhiryakova, D., Radchenkova, N., Kambourova, M. Acidolysis of
13.
14.
Tripalmitin with Oleic Acid Catalyzed by a Newly Isolated Thermostable
Lipase. J. Am. Oil Chem. Soc., 85, 129-132, 2008.
Guncheva, M., Zhiryakova, D., Radchenkova, N., Kambourova, M. 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, 2007.
Guncheva, M., Zhiryakova, D., Radchenkova, N., Kambourova, M. Properties of
immobilized lipase from Bacillus stearothermophilus MC7. Acidolysis of triolein
with caprylic acid. World Journal of Microbiology and Biotechnology (in press),
2009.
15. Kabaivanova, L., Dobreva E., Emanuilova, E., Chernev, E., Samuneva, B.,
Salvado, I. Synthesis, structure and application of new hybrid nanomaterials for
cell immobilization. Minerva Biotechnol, 18, 23-29, 2006.
16. Kabaivanova, L., Dobreva, E., Dimitrov, P., Emanuilova, E. Immobilization of
cells
17. Kabaivanova, L., Emanuilova, E., Chernev, G., Samuneva, B., Djambaski, P.,
Miranda Salvado I. M. Comparative study of two types of hybrid biocatalysts
applied in a biodegradation process. Minerva Biotechnol., 19, 57-63, 2007.
18. Kabaivanova, L., Emanuilova, E., Dimitrov, P., Engibarov, S., Boyadzhieva, I.,
Dobreva, E. 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, 2008.
19. Kambourova, M., Mandeva, R., Fiume, I., Maurelli, L., Rossi, M., Morana, A.
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. Vol. 102, issue 6, 1586–1593,
2007.
20. Kambourova, M., Mandeva, R., Dimova, D., Poli, A., Nicolau,s B., Tommonaro
G. Production and characterization of a microbial glucan, synthesized by
Geobacillus tepidamans V264 isolated from Bulgarian hot spring. Carbohydrate
Polymers, 2009 (in press).
21. L. Callewaert, B. Masschalck, D. Deckers, D. Nakimbugwe, M. Atanassova, A.
Aertsen, C. W. Michiels “Purification of Ivy, a lysozyme inhibitor from E. coli,
and characterization of its specificity for various lysozymes”. Enzyme Microb
Tech, No 2, pp. 205 – 211, 2005.
22. 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., 108, 355-363, 2006.
23. 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.
24. Safarikova M., Atanasova N., Ivanova V., Weyda F., Tonkova A. Cyclodextrin
glucanotransferase synthesis by semicontinuous cultivation of magnetic
biocatalysts fron cells of Bacillus circulans ATCC 21783. Process Biochem, 42,
1454-1459, 2007.
25. Samuneva, B., Djambaski, P., Kashchieva, E., Chernev, G., Kabaivanova, L.,
Emanuilova, E., Salvado, I.M.M., Fernandes M.H.V., Wu, A. Sol-gel synthesis
and structure of silica hybrid biomaterials . J. Non-Cryst. Solids, 354/2-9:733-740,
2007.
26. Samuneva, B., Djambaski, P., Kashchieva, E., Chernev, G., Kabaivanova, L.,
Emanuilova, E., Salvado, I.M.M., (...), Wu, A. Sol-gel synthesis and structure
of silica hybrid biomaterials J. Non-Cryst Solids 354 (2-9), pp. 733-740, 2008.
27. Samuneva, B., Kabaivanova, L., Chernev, G., Djambaski, P., Kashchieva, E.,
Emanuilova, E., Miranda Salvado, I.M., (...), Wu, A. Sol-gel synthesis and
structure of silica hybrid materials J Sol-Gel Sci Techn 48 (1-2), pp. 73-79,
2008.
28. Vassileva A., Atanasova N., Ivanova V., Dhulster P., Tonkova A.
Characterization of cyclodextrin glucanotransferase from Bacillus circulans
ATCC 21783 in terms of cyclodextrin production. Ann Microbiol, 57 (4) 609-615,
2007.
29. Vassileva, A., Beschkov, V., Ivanova, V., Tonkova, A. Continuous cyclodextrin
glucanoransferase production by free and immobilized cells of Bacillus circulans
ATCC 21783 in bioreactors. Process Biochem 3290-3295, 40, 2005.
with nitrilase activity from a thermophilic bacterial strain. J Ind Microbiol
Biotechnol 7-11, 32, 2005.
Scientific staff of the Department of Extremophilic Bacteria
1.
2.
3.
4.
5.
6.
7.
8.
9.
Assoc. Prof. Margarita Kambourova
Assoc. Prof. Alexandra Tonkova
PhD Anna Derekova
PhD Ivanka Bojadzhieva
PhD Iva Tomova
Researcher Nadja Kirilova
Researcher Nikolina Atanasova
Researcher Tzvetina Kitayska
Researcher Iva Ivanova