IM-BAS/IM-star web/… · Web viewHead of Department. Dimitrina Spasova, PhD, Associate Professor. Staff. Stoyanka Stoitsova, PhD, Associate Professor. Spasimira Radoevska, MS,

DEPARTMENT OFMORPHOLOGY OF MICROORGANISMS AND

ELECTRON MICROSCOPY

HEAD OF DEPARTMENT

Dimitrina Spasova, PhD, Associate Professor

STAFF

Stoyanka Stoitsova, PhD, Associate ProfessorSpasimira Radoevska, MS, Research AssistantMimi Jordanova, MS, Research AssistantLjubomir Danailov, MS, Research AssistantTsvetelina Paunova, MS, Research AssistantNina Tadjer, BS, Laboratory AssistantLidana Panova, photographer

PHD STUDENT - Anna Vacheva, MS

Dimitrina Spasova, PhD, Associate Professor

Head of DepartmentTel: (+359 2) 979 31 04

E-mail: [email protected]

1943 Born, July 20, Sofia1966 MS, Faculty of Biology, Sofia University ‘St. Kliment Ohridski’1975 Research Scientist, Institute of Microbiology, BAS1986 PhD in Microbiology, Institute of Microbiology, BAS1988 Visiting Scientist, Institute of Microbiology and Institute of Biochemistry, Academy of Sciences of the

USSR, and VNII of Antibiotics, Moscow, Russia1991 Associate Professor, Institute of Microbiology, BAS2004 Head of Department of Morphology of Microorganisms and Electron Microscopy

MAIN RESEARCH TOPICS

Fine structural characteristics (transmission and scanning electron microscopy) of microorganisms from diverse phylogenetic groups – viruses, prokaryotes (bacteria, actynomicetes) and eukaryotes (щeast, fungi) in relation to growth phase or cultivation conditions.

Morpho-functional investigations of microbial cells organization and its changes under the influence of various factors by means of electron microscopic cytochemistry. The cellular localization of enzymes is confirmed by rections with specific substrates resulting in deposition of electron dense products. The localization of enzymes and antigens is also clarified by immunocytochemistry. Lectin-gold conjugates are applied to trace the distribution of polysaccharides with defined non-reducing sugar termini.

Studies of the submicroscopic changes of microbial cells under the action of surface-active agents of synthetic origin (surfactants) and biosurfactants.

Investigations on the morphology, distribution patterns and degree of growth, reproduction and vitality of cells from strains-producers of biologically active substances immobilized on various carriers (nanomaterials, etc.) with the aim of estimation of appropriate production parameters.

Pathogenic Escherichia coli: cytochemical and ultrastructural analysis of the effects of physicochemical and biogenic factors on the cell surface variability (with special reference to polysaccharide variation) and the development of biofilms on materials used in medical practice.

MOST IMPORTANT ACHIEVEMENTS

The ultracytochemical localization of acid phosphatase in nongerminating and germinating conidia of the fungus Humicola lutea is established for the first time. The distribution in the mycelia is clarified.

Original evidence is obtained about the fine structural changes of model Gram-positive and Gram-negative bacteria under the action of rhamnolipid-biosurfactant with surface-active properties.

mailto:[email protected]

The ultrastructural peculiarities, the growth and reproductive capacity of producers of thermostable exo-inulinase and cyclodextrin glucanotransferase immobilized on different matrices (polysulphone membranes, agar gel) are characterized.

A correlation is determined between the ultracytochemical localization of succinate dehydrogenase of some bacteria and the changes in the lipoproteid content of their membranes under the action of Lubrol W.

Original cytochemical evidence is collected for the cell-surface and intracellular distribution of polysaccharides with defined lectin-binding capacity in some Gram-negative and Gram-positive bacteria.

SELECTED PUBLICATIONSCherepova, N., Spasova, D., Radoevska, S. (2001): Ultrastructural localization of succinate dehydrogenase in some

bacteria after treatment with Lubrol W1. Microbios 104, 49-54.

Uzunova, K., Vassileva, A., Ivanova, V., Spasova, D., Tonkova, A. (2002). Thermostable exo-inulinase production by semicontinuous cultivation of membrane-immobilized Bacillus sp. 11. cells. Process Biochemistry 37, 863-868.

Stoitsova, S. (2002): Presence and cellular distribution of soybean agglutinin-binding epitopes in two strains of Bacillus subtilis. Folia Microbiologica 47, 654-658.

Aleksieva, P., Spasova, D., Radoevska, S. (2003): Acid phosphatise distribution and localization in the fungus Humicola lutea. Z. Naturforsch. 58C, 239-243.

Stoitsova, S., Boteva, R., Doyle, R. (2003): Binding of hydrophobic ligands by Pseudomonas aeruginosa PA-I lectin. Biochim. Biophys. Acta 1619, 213-219.

Stoitsova, S., Grubhoffer, L., Nebesarova, J. (2003): Exposed and hidden lectin-binding epitopes at the surface of Borrelia burgdorferi. Folia Microbiologica 48, 654-658.

Stoitsova, S., Ivanova, R., Dimova, I. (2004): Lectin-binding epitopes at the surface of Escherichia coli K-12: examination by electron microscopy with special reference to the presence of a colanic acid-like polymer. J. Basic Microbiol. 44, 296-304.

Markova, N., Michailova, L., Kussovski, V., Jodanova, M., Radoucheva, T. (2005): Intranasal application of Lentinan enhances bactericidal activity of rat alveolar macrophages against Mycobacterium tuberculosis. Pharmacie 60, 42-48.

Michailova, L., Kussovski, V., Radoucheva, T., Jordanova, M., Berger, W., Rinder, H., Markova, N. (2005): Morphological variability and cell wall deficiency of Mycobacterium tuberculosis in ‘heteroresistant’ strains isolated from newly diagnosed tuberculosis patient. Int. J. Tuberc. Lung Dis. 9, 907-914.

Boteva, R., Bogoeva, V., Stoitsova, S. (2005): PA-I lectin from Pseudomonas aeruginosa binds acyl homoserien actones. Biochim. Biophys. Acta 1747, 143-149.

Bivolarska, M., Velinov, T., Stoitsova, S. (2006). Guided-wave and ellipsometric imaging of supported cells. Journal of Microscopy 224, 42-248.

Spasova, D., Aleksieva, P., Nacheva, L., Radoevska, S. (2007): Ultracytochemical localization of acid phosphatase in Humicola lutea conidia and mycelia. Z. Naturforsh. 62C (in press).

Angelova, B., Fernandes, P., Spasova, D., Mutafov, S., Pinheiro, HM., Cabral J.M.S. (2006): Scaning electron microscopy investigations on bis (2-ethylhexil) phthalate treated Mycobacterium cells. Microscopy Research and Technique. 69, 613-617,.

Sotirova, A., Spasova, D., Vasileva-Tonkova, E., Galabova, D. (2007): Effects of rhamnolipid-biosurfactant on cell surface of Pseudomonas aeruginosa. Microbiol. Res. (in press).

Michailova, L., Kussovski, V., Radoucheva, T., Jordanova, M. (2007): Persistence of Staphylococcus aureus L-forms during experimental lung infection in rats. FEMS Microbiol. Lett. (in press).

DEPARTMENT OF MICROBIAL BIOCHEMISTRY

HEAD OF DEPARTMENTDanka Galabova, PhD, Associate Professor

STAFF

Ignat Abrashev, PhD, DSc, Associate ProfessorEvgenia Vasileva-Tonkova, PhD, Associate ProfessorBlaga Angelova, PhD, Research ScientistBorjana Tuleva, PhD, Research ScientistNelly Christova, PhD, Research ScientistTatyana Avramova, PhD, Research ScientistPetya Orozova, PhD, Research ScientistAnna Sotirova, Research ScientistLilyana Stefanova, MS, Research AssistantDaniela Stoyanova, MS, Research Assistant

PHD STUDENT

Nadejda Fuchedjieva, MS

Danka Galabova, PhD, Associate Professor

Head of DepartmentTel: (+359 2) 979 3130


1969 MS, Faculty ofChemistry, Sofia University ‘St. Kliment Ohridski’1971, 1976,1978 Visiting Scientist, Salford University, England

1986 Research Scientist, Institute of Microbiology, BAS1986 PhD in Microbiology, Institute of Microbiology, BAS1986-1987 Visiting Scientist, University of South Carolina, Columbia SC, USA1998 Associate Professor, Institute of Microbiology, BAS2003 Head of the Department of Microbial Biochemistry, Institute of Microbiology, BAS


Microbial enzymes: neuraminidases, phosphatases, protein phosphatases, proteases, nucleases – mechanism of secretion, isolation, purification, properties, biological role. Microbial surfactants (biosurfactants) – biosynthesis, isolation, purification, physicalchemical properties; effect on microbial cell surface and properties. Microbial degradation of water insoluble compounds. Biochemistry and microbiology of anaerobic digestion. Microbial transformation of steroid compounds. Molecular analysis of microbial virulence factors.


Rhamnolipid- biosurfactant and its alginate complex caused changes in outer membrane components of Pseudomonas aeruginosa, which may improve the antibiotic – membrane interactions thus grounding in their application in the design of new more effective antimicrobial preparations.

Sialic acids were found for the first time in Pomorie mud, a finding with significant biological effects.

Information about the role of enzyme sialidase in the ecology of pathogenic bacteria from genera Vibrio and Aeromonas has been received.

Biosurfactant producing microbial strains from different genera were isolated when grown on hydrophobic substrates. The newly isolated glycolipid biosurfactants with effective surface and emulsifying properties are found promising for bioremediation application.

Microbial transformation of the steroid compounds sitosterol and androstenedione was performed by resting cells of Mycobacterium sp. and Rhodococcus sp., respectively, in a single phase organic solvent based medium.

A modified chemostat technique called titrostat was developed for selective isolation and continuous flow cultivation of rapidly growing bacteria utilizing toluene vapours as a single source of carbon and energy.


A simple and rapid test for differentiation of aerobic from anaerobic bacteria was developed applicable for determination of the respiratory type of pure cultures isolated from different areas of the environment.

SELECTED PUBLICATIONSVasileva-Tonkova, E., Galabova, D., Karpenko, E., Shulga, A. (2001): Biosurfactant-rhamnolipid effects on

yeast cells. Lett. Applied Microbiol. 33, 280-284.

Karakashev, D., Galabova, D., Simeonov, I. (2003): A simple and rapid test for differentiation of aerobic from anaerobic bacteria. World J. Microbiol. Biotechnol. 19, 233-238.

Vasileva-Tonkova, E., Galabova, D. (2003): Hydrolytic enzymes and surfactants of bacterial isolates from lubricant-contaminated wastewater. Z. Naturforsch. 58c, 87-92.

Sotirova A., Galabova D., Vasileva-Tonkova E. (2003): Effects of biosurfactant-rhamnolipid on bacterial growth

and protein release. Екологично инженерство и опазване на околната среда 3, 20-24.

Christova, N., Tuleva, B., Damyanova, B. (2004): Enhanced hydrocarbon biodegradation by a newly isolated Bacillus subtilis strain. Z. Naturforsch. 59c, 205-208.

Christova, N., Tuleva, B., Lalchev, Z., Jordanova, A., Jordanov, B. (2004): Rhamnolipid biosurfactants produced by Renibacterium salmoninarum 27BN during growth on n-hexadecane. Z. Naturforsch. 59c, 70-74.

Cruz, A., Angelova, B., Fernandes, P., Cabral, J.M.S., Pinheiro, H.M. (2004): Study of the key operational parameters for the side-chain cleavage of sitosterol by free mycobacterial cells in bis-(2-ethylhexyl) phthalate. Biocatalysis Biotransform. 22, 189-194.

de Carvalho, C.C.C.R., Cruz, A., Angelova, B., Fernandes, P., Pons, M.N., Pinheiro, H.M., Cabral, J.M.S., da Fonseca M.M.R. (2004): Behaviour of Mycobacterium sp. NRRL B-3805 whole cells in aqueous, organic-aqueous and organic media studied by fluorescence microscopy. Applied Microbiol. Biotechnol. 64, 695-701.

Mutafov, S., Angelova, B., Schmauder, H.-P., Avramova, T., Boyadjieva, L. (2004): Stoichiometry of microbial continuous-flow purification of toluene contaminated air. Applied Microbiol. Biotechnol. 65, 228-234.

Abrashev, I., Dulgerova, G., Dolashka-Angelova, P., Voelter, W. (2005). Purification and characterization of a novel sialidase from a strain of Arthrobacter nicotiane. J. Biochem. 137, 365-371.

Abrashev, I., Orozova, P. (2005):. Influence of mucins in natural mud from Pomorie salty lake on the growth and neuraminidase secretion of some Vibrio cholerae non 0-1 strains. Comptes rend. de l`Acad. Bulg. des Sci. 58, 1213-1218.

Angelova, B., Fernandes, P., Cruz, A., Pinheiro, H.M., Mutafov, S., Cabral, J.M.S. (2005): Hydroxylation of androstenedione by resting Rhodococcus sp. cells in organic media. Enzyme Microb. Technol. 37, 718-722.

Abrashev, I., Orozova, P. (2006): E. rhusiopathiae neuraminidase and its role in pathogenicity. Z. Naturforsch. 61c, 434-438.

Vasileva-Tonkova, E., Galabova, D., Stoimenova, E., Lalchev, Z. (2006): Production and properties of biosurfactants from a newly isolated Pseudomonas fluorescens HW-6 growing on hexadecane. Z. Naturforsch. 61c, 553-559.

Sotirova, A., Spasova, D., Vasileva-Tonkova, E., Galabova, D. (2007): Effects of rhamnolipid- biosurfactant on cell surface of Pseudomonas aeruginosa. Microbiol. Research (in press).

DEPARTMENT OF MICROBIAL GENETICS

HEAD OF DEPARTMENT

Nedka Shivarova, MD, PhD’ Associate Professor

STAFF

Zlatka Alexieva, PhD, Associate ProfessorKantcho Lahtchev, PhD, Associate ProfessorSvetla Danova, PhD, Associate ProfessorBlagoy Atanasov, PhD, Research ScientistNadejda Peneva, Research ScientistMaria Guerginova, PhD, Research ScientistDimitrina Liutzkanova, PhD, Research ScientistMargarita Stoilova-Disheva, PhD, Research ScientistPenka Petrova, PhD, Research ScientistGalina Stoiantcheva, PhD, Research ScientistRalitza Alexandrova, MS, Research ScientistDionora Guliamova, PhD, Research AssistantVasselka Peltekova, Research Assistant

PHD STUDENT: Jordan Manasiev

Nedka Shivarova, MD, PhD’ Associate Professor

Head of DepartmentTel: (+359 2) 979 31 14


Born 1971 MD in Human Medicine, Medical University, Sofia1978 MD in Medical Microbiology, Medical University, Sofia

Research Scientist, Institute of Microbiology, BAS1987 PhD in Microbiology, Institute of Microbiology, BAS1990 Associate Professor, Institute of Microbiology, BAS

Head of the Department of Microbial Genetics, Institute of Microbiology, BAS1998 Expert in environmental protection, Agency for Environmental Protection


Genetic and enzymological studies on microbial degradation of xenobiotics by filamentous yeasts.

Mathematical modelling of the phenol biodegradation process.

Molecular taxonomic studies of lactic acid bacteria and bacilli.

Biological activity and potential of lactic acid bacteria as bioprotective starters for dairy products and their probiotic properties for human health.

Ecological studies of the mosquito pathogen Bacillus sphaericus.

Molecular genetic investigation on some genes, involved in spectinomycin biosynthesis in Streptomyces.

Genetic and enzymological studies on methilotrophic yeasts.


The physiological and biochemical peculiarities of the original yeast strain Trichosporon cutaneum R57, which is highly active in degrading many aromatic and aliphatic compounds – toxic pollutants of the environment were investigated. The biochemical analysis of the first three enzymes of the catabolic pathway of degrading phenol in carbonless media enhanced the elucidating of their key role in the process. A system for homologous and heterologous protoplast fusion and protoplast transformation of Trichosporon cutaneum R57 strain was elaborated. A specific oligoneucleotide probe was applied for the identification of microbial strains with the potential of degrading toxic aromatic compounds, isolated from polluted soils and waters. Dot-blot hybridization analysis for the identification of catabolic genes, coding enzymes with phenol-hydroxilase activity was carried out.


Original approaches to the molecular-taxonomic characterization of lactic acid producing bacteria and the rapid monitoring of Lactobacilli from different ecological niches were developed.

The genetic, physiological and other factors, controlling the sexual process of the yeast Hansenula polymorpha were investigated. Two special types of homothalism were uncovered: a copulation potential in all possible combinations and sporulation of haploid strains.

SELECTED PUBLICATIONSLyutskanova, D., Stoilova-Disheva, M. (2003): Expression of the spcN gene from Streptomyces flavopersicus in

Escherichia coli and determination of the gene function. J. Biotechnol & Biotechnol. Eq. 17, 100-104.

Lyutskanova, D., Stoilova-Disheva, M., Peltekova, V. (2005): Increase in tylosin production by a commercial strain of Streptomyces fradiae. Appl. Biochem. Microbiol. 41, 165–168.

Lahtchev, K.L. Basic genetics of Hansenula polymorpha. In:G.Gellissen(ed) Hansenula polymorpha: biology and applications.Wiley-VCH (2002), 8-20.

Lahtchev, K.L., Semenova, V.D., Tolstorukov, I.I, van der Klei, I.-J., Veenhuis, M. (2002): Isolation and properties of genetically defined strains of the methylotrophic yeast Hansenula polymorpha CBS4732 . Archives of Microbilogy 177, 150-158.

Ozimek, P., Van Dijk, R., Lahtchev, K., Gancedo, C., Wang, D.Y., Van Der Klei, I.J., Veenhuis M. (2003): Pyruvate carboxylase is an essential protein in the assembly of yeast peroxisomal oligomeric alcohol oxidase. Molecular Biology of the Cell 14, 786-797.

Aleksieva, Z., Ivanova, D., Godjevargova, T., Atanasov, B. (2002): Degradation of some phenol derivatives by Trichosporon cutaneum R57. Proc. Biochem. 37, 1215–1219.

Alexieva, Z., Gerginova, M., Zlateva, P., Peneva, N. (2004): Comparison of growth kinetics and phenol metabolizing enzymes of Trichosporon cutaneum R57 and mutants with modified degradation abilities. Enzyme and Microbial Technology 34, 242-247.

Godjevargova, T., Ivanova, D., Aleksieva, Z., Burdelova, G. (2006): Biodegradation of phenol by immobilized Trichosporon cutaneum R57 on modified polymer membranes. Process Biochemistry 41, 2342-2346.

Gerginova, M., Manasiev, J., Shivarova, N., Alexieva, Z., (2007): Influence of various phenolic compounds on phenol hydroxylase activity of a Trichosporon cutaneum strain. Zeitschrift fuer Naturforschung 62c (in press).

Gerginova, M., Dimova, N., Ivanova, D., Alexieva, Z. (2007): Studies on biodegradation of aromatic pollutants by a Trichosporon cutaneum yeast strain. Bioremediation of soils contaminated with aromatic compounds, NATO Science Series: IV. Earth and Environmental Sciences, vol. 76.

Stoyancheva, G., Danova, S., Boudakov, I. (2006) : Molecular identification of vaginal lactobacilli isolated from Bulgarian women, Antonie van Leeuwenhoek 90, 201-210.

Petrova, P., Miteva, V., Ruiz, J. A., del Solar G. (2003): Sequencing and analysis of the Streptococcus thermophilus plasmid pt38, Plasmid 50, 176-189.

Petrova, P., Gouliamova, D. (2006): Rapid screening of plasmid-encoded small hsp-genes in Streptococcus thermophilus, Current Microbiology 53, 422–427.

Danova, S.T., Stoyancheva, G., Manasiev, Y., Miteva V. (2005): Development and application of random DIG labelled probes based on total genomic Lactobacillus DNA, World Journal of Microbiology & Biotechnology 21, 835–842.

Danova, S., Petrov, K., Pavlov, P., Petrova, P. (2005): Isolation and characterization of Lactobacillus strains involved in koumiss fermentation, International Journal of Dairy Technology 58, 100-105.

Miteva, V., Boudakov, I., Ivanova-Stoyancheva, G., Mitev, V., Mengaud, J. (2001): Differentiation of Lactobacillus delbrueckii subspecies by ribotyping and amplified ribosomal DNA restriction analysis (ARDRA), J. Appl. Microbiol. 90, 909-918.

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DEPARTMENT OF MICROBIAL BIOSYNTHESIS AND BIOTECHNOLOGIES

HEAD OF DEPARTMENTMladenka Paunova Ilieva-Stoilova, DSc, Professor

STAFF

Bonka Tzvetkova, PhD, Associate ProfessorAlexander Ratkov, PhD, Associate ProfessorPenka Alexieva, PhD, Associate ProfessorVeneta Ivanova, PhD, Associate ProfessorEmilina Simova, PhD, Associate ProfessorTsonka Christozova, PhD, Associate ProfessorDora Beshkova, PhD, Associate ProfessorKostantza Pavlova, PhD, Associate ProfessorGinka Frengova, PhD, Associate ProfessorAdriana Gousterova, PhD, Associate ProfessorAtanas Pavlov, PhD, Associate ProfessorVictoria Gesheva, PhD, Research ScientistVessela Raykovska, MS, Research ScientistLiliana Nacheva, MS, Research ScientistDimka Tuneva, PhD, Research AssistantMariana Kolarova, MS, Research AssistantKrasya Aleksieva, MS, Research AssistantVelitchka Ivanova, MS, Research AssistantJulia Krusteva, MS, Research AssistantPhilip Philipov, MS, Research AssistantDonka Paskaleva, MS, Research AssistantKalin Todorov, MS, Research AssistantMart Mihailov, MS, Research AssistantIgnat Dimov, MS, Research AssistantTatyana Gocheva, MS, Research AssistantVasil Georgiev, MS, Research AssistantSvetla Kostadinova, Research AssistantElka Genova, Laboratory AssistantStefka Vassileva, Laboratory AssistantVasilkaUsherova, Laboratory Assistant

Mladenka Paunova Ilieva-Stoilova, DSc, Professor



1939 Born March 24, Kostinbroad, Bulgaria1962 MS, Faculty of Chemistry, Sofia University ‘St. Kliment Ohridski’1963 Research Scientist, Higher Institute of Food and Flavour Industries, Plovdiv1973 PhD in Biotechnology, Higher Institute of Food and Flavour Industries1980 Associate Professor, Higher Institute of Food and Flavour Industries1982 Associate Professor, Institute of Microbiology, BAS2000 DSc in Biotechnology, Institute of Microbiology, BAS1993 Coordinator of the Research Group in Plovdiv, Institute of Microbiology, BAS2000 DSc, Institute of Microbiology, BAS2005 Head of the Department of Microbial Biosynthesis and Biotechnologies, Institute of Microbiology,

BASTeaching: 1963-95 Higher Institute of Food and Flavour Industries


The research is concentrated on the metabolism of prokaryotic and eukaryotic cells and the possibilities for its regulation. On this base the biotechnology of production of biologically active substances for medicine and starters and additives for food industry are developed. The following aspects are studied:

Yeasts – physiology and biochemistry of methylotrophic, beaker’s and fodder’s yeast and biosynthesis of biologically active substances; biological diversity of psyhrophilic yeasts from Livingston island – Antarctica and production of biologically active substances (enzymes, lipids and polysaccharides) by them.

Actinomycetes and filamentous fungi - physiology, biochemistry, biosynthesis and identification of primary and secondary metabolites. The investigation are focused on: Actinomycetes – taxonomy, physiology, biochemistry and biosynthesis of enzymes, antibiotics and stimulators; Isolation, purification and structure of biologically active substances; Filamentous fungi – optimization of conditions for production of extracellular hydrolytic enzymes by free and immobilized cells. Characteristics of the obtained enzyme preparations and investigation of possibilities of their application.

Lactic acid bacteria - physiology and resources for development of dairy products whit improved nutritional value. The work is focused on the physiology and resources of lactic acid bacteria, and health solutions. That involves creation of effective bio-consortium cultures for fermented milk with improved physiological and nutritional value by: Incorporation of antimicrobial agents with wide inhibitory spectrum to selected starter cultures for implementation of the protective functions and of biocontroling agents – regulation of the microflora, directing of the processes of forming and ripening of Bulgarian dairy products and participation in the


biotransformation of the milk substances; The proteolytic systems of lactic acid bacteria and association of selected lactobacillus strains with high peptidolytic profilesis studied. New approaches for development of dairy products with high biological (health) benefits and nutritive value, quality and safety.

Amino acids – biotechnologies for their production.

Biological active substances by plant in vitro systems. The possibilities of different plant in vitro systems for the production of low molecular weight biologically active substances (including additives and antioxidants for food industries), enzymes and polysaccharides are investigated. The research concerns optimization of the biosynthetic processes, isolation, purification and identification of the obtained metabolites. Special attention is drawn to application of different strategies for enhancement of the yield and effectiveness of biotechnological processes (selection, elicitation, two-phase cultivation etc.).


A method for production of extra cellular α-galactosidase was developed by submerged cultivation of Aspergillus niger M47 , Penicillium chrisogenum LN33 and Humicula lutea 1205 on the medium, composed by wastes from food industry. The method was submitted for patent.

A Lab biotechnology for galanthamine production by Leucojum aestivum shoot culture was developed. This is the first bioreactor process reported for production of Galanthamine by in vitro plant system.

A detailed “know-how” for production of L-lysine and a Lab biotechnology for production of L-valine were developed.

From culture medium of a thermophilic strain two indole alkaloids (microbiareton and microbiaeratinin) were isolated and their cytotoxic and antialgic activities were established.

An alkaline hydrolysate from animal wastes was obtained and their influence on chemical and microbiological properties of the poor soils were investigated. The obtained results outlined the possibilities for its application as an organic fertilizer.

The growth of methylotrophic yeasts Hansenula and Pichia on glucose, methanol and glycerol as carbon source was investigated. The presence of catalase and superoxide dismutase (SOD) activity in fractions of mitochondria, cytosol and peroxisomes were investigated. It was established that peroxisomal catalase was located in the mitochondrial matrix and SOD( besides the typical places for localization- mitochondria and cytosol)was detected in peroxisomes as well.

The proteolytic system of starter lactobacteria was characterized and it was established that this system is a criterion for their participation in starters for milk products.

In situ baceriocins production of LB. bulgaricus BB18 and LB. lactis BCM5 was studied and their strain compatibility with two technological strains S. thermophilus 11A and Lb. bulgaricus LX1 was demonstrated for forming starters for fermented milks with health benefits.

The strain Streptomyces sp., producer of antibiotic complex, was identified by hemotaxonomic and genetic methods as Streptomyces iakurus DSM 41873. The

antibiotic complex is composed of 5 new components, which were characterized by their molecular masses and chemical structures.

The colloid properties of glucomannan, synthesized by psychrophilic stain were studied. The comparison of the cream emulsions with glucomannan and those with emulsifiers rofetan and arlacel ( used in cosmetic industry) showed that they were with equal stability.

The yeast strain, producer of phytase was isolated from Antarctic samples. The appropriate culture medium and parameters of cultivation were established for high production of phytase. The enzyme kinetics and properties were determined as well.

By flow cytometry the genom sizes of the cells of Beta vulgaris intact plants and hairy root cultures were determined. It was established that in contrast to the primary plant tissues, the obtained hairy roots are mixoploids., due to several cycles of endoreduplication. Such difference currently is not reported in the available scientific literature.

SELECTED PUBLICATIONSIlieva, M., Pavlov, A., Kovatcheva, E. (2002): Further Research into Lavandula Species: Cell Cultures of

Lavandula vera and Rosmarinic Acid Production - In: Genus Lavandula – series “Medicinal and Aromatic Plants (M. Lis-Balchin - ed) – Taylor & Francis Publishers, 214-226– ISBN 0-415-28486.

Hristozova, Ts., Michailova, L., Tuneva, D., Gotcheva, V., Angelov, A., Roshkova, Z. (2002): Mutant Hansenula polymorpha with constitutive alcohol oxidase and peroxisome biosynthesis. Z. Naturforsch. 57c, 858-862.

Hristozova, Ts., Rasheva, T., Nedeva, T., Kujumdzieva, A. (2002): Superoxide dismutase duringng glucose repression of Hansenula polymorpha CBS 4732. Z. Naturforsch. 57c, 313-318.

Hoshino,Y., Ivanova, V., Yazawa, K., Ando, A., Mikami, Y., Zaki, S., Karam, Z., Youssef, Y., Graefe, U. (2002): Queenslandon, a new antifungal compound produced by Chrysosporium queenslandicum: Production, isolation and structure elucidation. J. Antibiotics 55, 516-520.

Ivanova,V., Aleksieva, K., Kolarova, M., Chipeva, V., Schlegel, R., Schlegel, B., Graefe, U. (2002): Neuropogonines A, B and C, new depsidon-type metabolites from Neuropogon sp., an Antarctic lichen. Die Pharmazie 57, 73-74.

Ivanova, V., Hoshino, Y., Yazawa, K., Ando, A., Mikami, Y., Graefe, U. (2002): Isolation and structure elucidation of two new antibacterial compounds, produced by Chrysosporium queenslandicum. J. Antibiotics 55, 914-919.

Simova, E., Beshkova, D., Angelov, A., Hristozova, T., Frengova, G., Spasov, Z. (2002): Lactic acid bacteria and yeast in kefir grains and in kefir obtain with them. J. Ind. Microbiol. Biotechnol. 28, 1-6.

Gesheva, V. (2002): Rhizosphere microflora of some citrus as a source of antagonistic actinomycetes. Eur. J. Soil Biol. 38, 85-88.

Aleksieva, P., Spasova, D., Radoevska, S. (2003): Acid phosphatase distribution and localization in the fungus Humicola lutea. Z. Naturforsch. 58c, 239-243.

Aleksieva, P., Tchorbanov, B., Michailova, L., Nacheva, L. (2003): Improvement of acid phosphatase production by immobilization of Humicola lutea mycelium in polyurethane sponge. World J. Microbiol. Biotechnol. 19, 247-253.

Berkov, S., Pavlov, A. (2004): A rapid densitometric method for the analysis of hyoscyamine and scopolamine in solanaceous plants and their transformed root cultures. Phytochem Analysis 15, 141-145.

Simova, E., Frengova, G., Beshkova, D. (2004): Exopolysaccharides produced by mixed culture of yeast Rhodotorula rubra GED10 and yogurt starter (Strepto-coccus thermopilus 13a + Lactobacillus bulgaricus 2-11). J. Appl. Microbiol. 97, 512-519.

Goshev, I., Gousterova, A., Vasileva-Tonkova, E., Nedkov, P. (2005): Characterization of the enzyme complexes produced by two newly isolated thermophylic actinomycete strains during growth on collagen-rich materials. Process Biochem. 40, 1627-1631.

Gousterova, A., Braikova, D., Goshev, I., Christov, P., Tishinov, K., Vasileva-Tonkova, E., Haertlé, Т., Nedkov, P. (2005): Degradation of keratin and collagen containing wastes by newly isolated thermoactinomycetes or by alkaline hydrolysis . Lett. Appl. Microbiol. 40, 335-34.

Angelov, A., Gotcheva, V., Hristozova, Ts., Gargova, S. (2005): Application of pure and mixed probiotic lactic acid bacteria and yeast cultures for oat fermentation. J. Science Food and Agriculture 85, 2134-2141.

Gesheva, V. (2005): Microbiota of subantarctic soils from South Georgia Island. Cyprus J. Sci. 3, 75-81.

Gesheva, V., Ivanova, V., Gesheva, R. (2005): Effects of nutrients on the production of AK-111-81 macrolide antibiotic by Streptomyces hygroscopicus. Microbiological Research 160, 243-248.

Pavlov, A., Popov, S., Kovacheva, E., Georgiev, M., Ilieva, M. (2005): Volatile and polar compounds in Rosa damascene Mill 1803 cell suspension. Journal of Biotechnology 118, 89-97.

Pavlov, A, Georgiev, V, Ilieva, M. (2005): Betalain biosynthesis by red beet (Beta vulgaris L.) hairy root culture. Process Biochemistry 40, 1531-1533.

Simova, E., Simov, Zh., Beshkova, D., Frengova, G., Dimitrov, Zh., Spasov, Z. (2006): Amino acid profiles of lactic acid bacteria, isolated from kefir grains, and kefir starter made from them. Int. J. Food Microbiol. 107, 112-123.

Simova, E., Beshkova, D. (2006): Effect of growth phase and growth medium on the peptidase activities of starter lactobacteria. Le Lait, Dairy Science Technol. (in press).

Hristozova, Ts., Angelov, A., Tzvetkova, B., Paskaleva, D., Gotcheva, V., Gargova, S., Pavlova, K. (2006): Effect of furfural on carbon metabolism key enzymes of lactose-assimilating yeasts. Enzyme Microb. Technol. 39,1108-1112.

Georgiev, M., Kuzeva, S, Pavlov A., Kovacheva, E., Ilieva, M. (2007): Elicitation of rosmarinic acid by Lavandula vera MM cell suspension culture with abiotic elicitors - Word Journal of Microbiology and Biotechnology 23, 301-304.

Pavlov, A., Berkov, S., Courot, E., Gotcheva, T., Tuneva, D., Pandova, B., Georgiev, M., Georgiev, V., Yanev, S., Burrus, M., Ilieva, M. (2007): Galanthamine production by Leucojum aestivum in vitro systems, Process Biochem. in press, doi: 10.1016/j.procbio.2006.12.2006

Georgiev, M.., Pavlov, A., Bley, T. (2007): Hairy root type in vitro systems as sources of bioactive substances. Appl. Microbiol. Biotechnol. (in press), DO1 1o.1007/300253-007-0856-5.

DEPARTMENT OF MICROBIAL ECOLOGY

STAFF

Sava Mutafov, PhD, Associate ProfessorAlexandar Hristov, PhD, Research ScientistDessislava Todorova, MS, Research AssistantMaria Ianis, MS, Research AssistantVera Dencheva, MS, Research AssistantYulia Bebova, MS, Research Assistant

Kolishka Tsekova, PhD, Associate Professor



1950 Born November 17, Tsareva poliana, Haskovo1973 MS, Faculty of Chemistry, Sofia University ‘St. Klimetn Ohridski’1974-77 ResearchAssistant, Institute of Wine Production, Ministry of Agriculture1978-82 Research Assistant, Institute of Microbiology. BAS1983 Research Scientist, Institute of Microbiology. BAS1985 PhD in Microbiology, Institute of Microbiology, BAS2003 Associate Professor, Institute of Microbiology. BAS2005 Head of the Department of Microbial Ecology, Institute of Microbiology. BASTeaching: 2003-05 University of Chemical Technology and Metallurgy, Sofia


Biosynthesis of biological active substances: organic acids and enzymes

Kinetics, modeling, optimization of biotechnological processes and their set-up in industrial scales

Investigation on physiological response of microorganisms to different pollution: heavy metals, pesticides, oil products

Biosorption of heavy metals by free and immobilized cells of filamentous fungi

Biological solubilization of rock phosphates with free and immobilized filamentous fungi.

Investigation on microbial diversity, structures and dynamics of microbial populations and processes development for waste water and soil purification.

The changes in the structure and function of microbial communities in river and marine ecosystems in the presence of xenobiotics were investigated.

MOST IMPORTANT ACHIEVEMENTS:

Original baker's yeast strains - Saccharomyces cerevisiae were selected. These strains have high trehalose content and high maltase activity.

Method for quantitative determination of biotin applying specially selected methanol utilizing yeast strain was elaborated.


Strains of Aspergillus niger producers citric and gluconic acids under double limitation of nitrogen and phosphorous during their cultivation were selected.

The mathematical model of growth and production of citric acid on different carbon sources was developed.

The strains bioindicators and detectors of heavy metal and pesticides pollution were selected.

Microbial association degrading phenol was selected.

SELECTED PUBLICATIONSTsekova, K., Dentcheva, V., Ianis, M. (2001): Copper uptake by Penicillium brevicampactum, Z.

Naturforschung 56c, 803-805.

Tsekova, K., Ilieva, S. (2001): Copper removal from aqueous solution using Aspergillus niger mycelia in free and polyurethane-bound form, Appl. Microbiol. Biotechnol. 55, 636-637.

Tsekova, K., Galabova, D., Todorova, K., Ilieva , S. (2002): Phosphatase activity and copper uptake during growth of Aspergillus niger, Process Biochemistry 37, 753-758.

Tsekova, K., Todorova, D. (2002): Copper (II) accumulation and superoxide dismutase activity during growth of Aspergillus niger B-77, Z. Naturforschung 57c, 319-322.

Tsekova, K., Petrov, G. (2002): Removal of heavy metals from aqueous solution using Rhizopus delemar mycelia in free and polyurethane-bound form, Z. Naturforschung 57c, 629-633.

Tsekova, K., Galabova, D. (2003): Phosphatase production and activity in copper (II) accumulating Rhizopus delemar, Enzyme and Microbial Technology 33, 926-931.

Mutafov S., Angelova B., Schmauder H.-P., Avramova T., Boyadjieva L. (2003): Titrostat: a reliable technique for continuous cultivation of microorganisms utilising liquid or gaseous water insoluble substrates. Bitechnology and Bioengineering 84,160-169.

Mutafov S., Angelova B., Schmauder H.-P., Avramova T., Boyadjieva L. (2004): Stoichiometry of microbial continuous-flow purification of toluene contaminated air. Applied Microbiology and Biotechnology 65, 228-234.

Angelova B., Bejar V., Mutafov S., Schmauder H.-P. (2004): Bioavailability of substrates in processes of biodegradation and biotransformation. CHISA 2004 - 16th International Congress of Chemical and Process Engineering, , p. 3543.

Angelova B., Fernandes P., Cruz A., Pinheiro H.M., Mutafov S., Cabral J.M.S. (2005): Hydroxylation of androstenedione by resting Rhodococcus sp. cells in organic media. Enzyme and Microbial Technolo 37, 718-722.

Angelova B., Mutafov S., Avramova T., Stefanova L. (2005): Effect of nitrogen source in cultivation medium on the 9α- hydroxylation of pregnane steroids by resting Rhodococcus sp. cells. Biotechnology and Biotechnological Equipment 19, 113-116.

Todorova, N., Ivanov, I., Hristov, A., Karamfilov, V. (2005): Application of Ardrea analysis for early warning of the effects of oil pollution in coastal marine ecosystems. Research into laboratory “Microcosm” model. Ecological Engineering and Environment Protection 3-4, 69-75.

Tsekova, K., Christova, D., Ianis M. (2006): Heavy metal biosorption sites in Penicillium cyclopium. J. Appl. Sci. Environ. Mgt. 10, 117-121.

Angelova, B., Fernandes, P., Spasova, D., Mutafov, S., Pinheiro, H.M., Cabral, J.M.S. (2006): Scanning electron microscopy investigations on bis(2-ethylhexyl)phthalate treated Mycobacterium cells. Microscopy Research and Technique, , 69, 613-617.

Mutafov, S., Avramova, T., Stefanova, L., Angelova, B. (2006): Decolorization of Acid Orange 7 by bacteria of different tinctorial type: a comparative study. World Journal Microbiol. Biotechnol., DOI 10.1007/s11274-006-9241-2,

DEPARTMENT OF MYCOLOGY

HEAD OF DEPARTMENTMaria B. Angelova, D.Sc., Professor

STAFF

Ljudmila Slokoska, PhD, Associate ProfessorSvetlana Pashova, MS, Research ScientistJana Gocheva, MS, Research ScientistEkaterina Krumova, MS, Research ScientistRadoslav Abrashev, MS, Research ScientistBorjana Spasova, MSc ResearchJeni Miteva, MSc, ResearchValentina Karakashjan

Maria B. Angelova, D.Sc., Professor

Head of departmentTel: (+359 2) 979 31 26


1970 MS Faculty of Biology, Sofia University ‘St. Kliment Ohridski’1976 Research Scientist, Institute of Microbiology, BAS1982 PhD in Micribiology, Institute of Microbiology, BAS1987 Associate Professor, Institute of Microbiology, BAS1989 Head of the Department of Mycology, Institute of Microbiology, BAS2003 DSc in Microbiology, Institute of Microbiology, BAS2005 Professor in Microbiology, Institute of Microbiology, BASTeaching:1987-88 Faculty of Biology, Sofia University ‘St. Kliment Ohridski’Since 2000 Supervisor of 3 PhD Students


Research within the Group is focused on filamentous fungi at different levels: molecular, cellular, whole organism and biocenotic.

Taxonomic identification of fungal species;

Fungal morphology, physiology and biochemistry under normophysiological and stress conditions;

Fungal cell response against different type of stresses (oxidative stress, heat- and cold shock, immobilization, heavy metals); evaluation of oxidative stress biomarkers; antioxidant enzyme defence;

Fungal cell factories for production of valuable biological-active compounds by free and immobilized cultures; cold-active enzymes; regulatory mechanisms in the biosynthesis; purification and characterization of enzymes;

Fungal biodegradation of natural and synthetic; mechanism of action of fungicide substances; methods for application of fungicides; laboratory expertise, consultations, instructions for preservation and elimination of fungi.


Fungal diversity: A sizeable fungal collection was developed along with the isolation of strains from temperate and extreme environments, including Antarctica.

Oxidative stress (OS) and relationship with other types of stresses: Filamentous fungi belonging to different genera were used as model microorganisms for investigation of cell response of the lower multicellular eukaryotes against OS. Treatment of the strains with various stimuli generating reactive oxygen species induces a state of OS evaluated by means of specific biomarkers and antioxidant


enzyme defence (SOD and CAT). Unusual existence of Cu/Zn-SOD in mitochondrial intermembrane space (IMS) was evidenced. This is the first identified naturally glycosylated enzyme, isolated from IMS. Our results provide new information that the OS plays a major role in copper toxicity and heat- and cold-shock response in filamentous fungi. Compared to temperate mesophilic strains, Antarctic fungi (psychrophilic and mesophilic) demonstrated adaptations, which permit survival in low-temperature conditions.

Fungi as cell factories for production of valuable biological-active compounds: High effective technology for biosynthesis of naturally glycosylated Cu/Zn-SOD by the fungal strain Humicola lutea 103 was elaborated. The novel enzyme (HLSOD) exerts a far higher pharmacological activity than non-glycosylated enzymes. HLSOD was fully characterized and used in in vivo animal models for the demonstration of its protective effect against Graffi tumor and influenza virus infection. This enzyme improves fertility of ram and bull spermatozoa during liquid storage and cryoconservation. A new direction in our work is related to biosynthesis of valuable cold-active enzymes in psychrophilic and psychrotrophic fungi, using existing collections of Antarctic strains.

Fungal biodegradation of natural and synthetic polymers: Due to the current knowledge about morphology and biochemistry of the filamentous fungi, as well as the professional experience some methods concerning the preservation of natural polymers from fungal biodegradation were developed.

SELECTED PUBLICATIONSAngelova, M., S., Pashova, L. Slokoska. (2000): Comparison of antioxidant enzyme biosynthesis by free and

immobilized Aspergillus niger cells. Enzyme Microbiol. Technol. 26, 544-549.

Angelova, M., P. Dolashka-Angelova, E. Ivanova, J. Serkedjieva, L. Slokoska, S. Pashova, R. Toshkova, S. Vassilev, I. Simeonov, H-J. Hartmann, S. Stoeva, U. Weser, W.Voelter. (2001): A novel glycosylated Cu/Zn-containing superoxide dismutase: production and potential therapeutic effect. Microbiology (UK) 147, 1641-1650.

Ivanova, I., M. Angelova, L. Slokoska, S. Pashova, R. Toshkova, P. Dolashka-Angelova, P. Dimitrova, W. Voelter, (2002): Effect of Cu/Zn-superoxide dismutase from the fungal strain Humicola lutea 103 on antioxidant defense of graffi tumor-bearing hamsters, Z. Naturforsch. 57c, 197-204.

Toshkova R., Ivanova E., Angelova, M., Dolashka P., Voelter W. (2003): Effect of the fungal Cu/Zn-superoxide dismutase on the cell-mediated immune response in tumor Graffi bearing hamsters. Z. Naturf. 58c, 128-134.

Serkedjieva, J., I. Roeva, M. Angelova, P. Dolashka, W. Voelter. (2003): Combined protective effect of a fungal Cu/Zn-containing superoxide dismutase and rimantadine hydrochloride in experimental murine influenza A virus infection. Acta Virol. 47, 53-56.

Stefanov R., Angelova, M., Stefanova Z., Subev M., Dolashka P., Voelter W., Zachariev Z. (2004): Cu/Zn-Superoxide dismutase from the fungal strain Humicola lutea 103 improves ram spermatozoa functions during liquid storage. Andrologia 2, 51-56.

Dolashka-Angelova P., Stevanovic S., Dolashki A., Angelova M., Pashova S., Krumova E., Serkejieva J., Zacharieva S., Voelter W. (2004): Structural and functional analyses of glycosylated Cu/Zn-SOD from the fungal strain Humicola lutea 103, cultivated in copper stress conditions. Biochem. Biophys. Res. Com. 317, 1006-1016.

Angelova M., Pashova S., Spasova B., Vassilev S., Slokoska S. (2005): Oxidative stress response of filamentous fungi induced by hydrogen peroxide and paraquat. Mycol. Res. 109, 150-158.

Sokmen M., Angelova, M., Krumova, E., Pashov, S., Ivanchev, S., Sokmen, A., Serkedjieva, J. (2005): In vitro antioxidant activity of polyphenol extracts with antiviral properties from Geranium sanguineum L. Life Sci. 76, 2981-2993.

Abrashev, R., P. Dolashka, R. Christova, L. Stefanova, M. Angelova (2005): Role of antioxidant enzymes in survival of conidiospores of Aspergillus niger 26 under conditions of temperature stress. J. Appl. Microbiol. 99, 902-905.

Gocheva, Y., Krumova, E., Slokoska, L., Miteva, J., Angelova, M. (2006): Cell response of Antarctic and temperate strains of Penicillium spp. to different growth temperature. Mycol. Res. 110, 1347-1354.

Stefanov R., E. Krumova, M. Angelova, P. Dolashka, W. Voelter and Z. Zachariev (2006): Artificial Insemination of Sheep and Cow with Semen Treated by Cu/ Zn-superoxide Dismutase from the Fungal Strain Humicola lutea 103. W J Zoology 1, 36-39.

Gocheva, Y., E. Krumova, L. Slokoska, V. Gesheva, M. Angelova (2005): Isolation of filamentous fungi from Antarctica. Compt. rend. Acad. bulg. Sci. 58, 403-408.

Abrashev, R., P. Dolashka, M. Angelova( 2005): Enhanced antioxidant enzyme activities in temperature-resistant variants of Aspergillus niger. Compt. rend. Acad. bulg. Sci. 58, 417-420.

Krumova, E., Dolashka-Angelova, P., Pashova, S., Stefanova, L., Van Beeumen, J., Vassilev, S., Angelova, M. (2006): Improved production by fed-batch cultivation and some properties of Cu/Zn-superoxide dismutase from the fungal strain Humicola lutea 103. Enzyme Microb Technol (in press).

DEPARTMENT OF EXTREMOPHILIC BACTERIA

HEAD OF DEPARTMENT

Margarita Kambourova, PhD, Associate Professor

STAFF

Elka Emanuilova, PhD, Associate ProfessorAlexandra Tonkova, PhD, Associate ProfessorRossitza Mandeva, PhD, Research ScientistLudmila Kabaivanova, PhD, Research ScientistMiroslava Atanassova, PhD, Research ScientistAnna Terziyska, MD, Research ScientistAnna Derekova, MS, Research ScientistAnna Vasileva, MS, Research ScientistStefan Engibarov, MD, Research ScientistNadja Kirilova, MS, Research AssistantNikolina Atanasova, MS, Research AssistantMaria Jordanova, Laboratory Assistant

Margarita Kambourova, PhD, Associate ProfessorHead of Department

Tel: (+359 2) 979


1958 Born July 22, 1958, Sofia1981 Diploma, Faculty of Biology, Sofia State University1986 PhD in Micribiology, Institute of Microbiology, BAS1986 Research Scientist, Institute of Microbiology1996-1997 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 2003 Associated Professor. Institute of Microbiology, BAS2004 Head of Department of Extremophilic Bacteria, Institute of Microbiology, BAS2004 NATO fellow,Institute of Protein Biochemistry, CNR, Naples, Italy

Teaching Since 1996 Faculty of Information Technologies, Specialty Bioinformatics, Sofia University

MAIN RESERCH TOPICS

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.

Biosynthetic capacity of extremophilic microorganisms to synthesize biotechnologically valuable enzymes. These organisms have been identified as industrially important due to the production of thermostable and alkaloresistent 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, nitrilase, gellan-lyase et al.

Purification and characterization of thermostable enzymes. 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. Data obtained were compared with the reported in literature enzymes and considered their biotechnological potential.

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.


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.

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.

SELECTED PUBLICATIONSUzunova, K., Vasileva, A., Kambourova, M., Ivanova, V., Spasova, D., Mandeva, R., Derekova, A., Tonkova,

A. (2001): Production and properties of a bacterial thermostable exo-inulinase. Z. Naturforsch. 56c, 1022-1028.

Kambourova, M., Tangney, M., Priest, F.G. (2001): Regulation of polyglutamic acid synthesis by glutamate in Bacillus licheniformis and Bacillus subtilis. Appl. Environ. Microbiol. 67, 1004-1007.

Uzunova, K., Vassileva, A., Ivanova, V., Spasova, D., Tonkova, A. (2002): Thermostable exo-inulinase production by semicontinuous cultivation of membrane-immobilized Bacillus sp. 11 cells. Process Biochemistry 37, 863-868.

Samuneva, B., Kadiyska, E., Djambaski, P., Dobreva, E., Bojadjieva, I., Kabaivanova, L. (2002): Sol-gel Synthesis of Glassy Hybrid Matrices for Cell Immobilization. Glass Science and Technology 75-C2, 434-437.

Kambourova, M., Kirilova, N., Mandeva, R., Derekova, A. (2003). Purification and properties of thermostable lipase from a thermophilic Bacillus stearothermophilus MC 7. J. Mol. Catal. B 22, 307-313.

Vassileva, A., Burhan, N., Beschkov, V., Spasova, D., Radoevska, S., Ivanоva, V., Tonkova, A. (2003): Cyclodextrin glucantransferase production by free and agar gel immobilized cells of Bacillus circulans ATTC 21783. Process Biochem. 38, 1585-1591.

Groudieva, T., Kambourova, M., Yusef, H., Royter, M., Grote, R., Trinks, H., Antranikian, G. (2004): Diversity and cold-active hydrolytic enzymes of culturable bacteria associated with Arctic sea ice, Spitzbergen. Extremophiles 8, 475-488.

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.

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.

Chernev, G., Samuneva, B., Djambaski, P., Salvado I.M., Fernandes, M.H., Kabaivanova, L. (2005): Silica Nanocomposites containing Polyacrylamide gel. Glass Technol. 46/2, 175-178.

Chernev, G., Samuneva, B., Djambaski, P., Salvado, L.M.M., Kabaivanova, L., Dobreva, E., Emanuilova, E. (2005): Whole living cell entrapment in nanomaterials for 4- cyanopyridine biodegradation XIII Intern. Workshop Bioencaps, Kingstone, Ontario (Canada) June 24-26, 57–60.

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, 321-326.

Kambourova, M., Mandeva, R., Fiume, I., Maurelli, L., Rossi, M., Morana, A. (2006): 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. (in press).

Tonkova, A. (2006): Microbial starch converting enzymes of the α-amylase family. In: Microbial Biotechnology in Horticulture (Ray, R.C. and Ward, O.P., eds.), v. 1, pp.421-472. Sci Publ. Inc., Enfield, NH, USA.

Kabaivanova, L., Dobreva, E., Emanuilova, E., Chernev, E., Samuneva, B., Solvado, I. (2006): Synthesis, structure and application of new hybrid nanomaterials for cell immobilization. Minerva Biotechnologica 18.

Documents

IM-BAS/IM-star web/… · Web viewHead of Department. Dimitrina Spasova, PhD, Associate Professor. Staff. Stoyanka Stoitsova, PhD, Associate Professor. Spasimira Radoevska, MS,