DEPARTMENT OF MICROBIAL BIOCHEMISTRY

Danka Galabova, PhD, Associate Professor

Head of Department

Tel: (+359 2) 979 3130

E-mail:

1969 / MS, Faculty ofChemistry, Sofia University ‘St. Kliment Ohridski’
1971, 1976,
1978 / Visiting Scientist, Salford University, England
1986 / Research Scientist, Institute of Microbiology, BAS
1986 / PhD in Microbiology, Institute of Microbiology, BAS
1986-1987 / Visiting Scientist, University of South Carolina, ColumbiaSC, USA
1998 / Associate Professor, Institute of Microbiology, BAS
2003 / Head of the Department of Microbial Biochemistry, Institute of Microbiology, BAS

Staff

IgnatAbrashev, PhD, DSc,AssociateProfessor

EvgeniaVasileva-Tonkova, PhD, AssociateProfessor

BlagaAngelova, PhD, Research Scientist

BorjanaTuleva, PhD, Research Scientist

NellyChristova, PhD, Research Scientist

TatyanaAvramova, PhD, Research Scientist

PetyaOrozova, PhD, Research Scientist

AnnaSotirova,Research Scientist

Lilyana Stefanova, MS, Research Assistant

Daniela Stoyanova,MS, Research Assistant

PhD Student

Nadejda Fuchedjieva, MS

Main Research Topics

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.

Most Important Achievements

  • 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 Publications

Vasileva-TonkovaE., D. Galabova, E. Karpenko, A. Shulga. Biosurfactant-rhamnolipid effects on yeast cells. Lett. Applied Microbiol., 2001, 33, 280-284.

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

Tuleva, B., G. Ivanov, N. Christova. Biosurfactant production by a new Pseudomonas putida strain. Z. Naturforsch., 2002, 57c, 356-360.

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

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

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

SotirovaA., GalabovaD., Vasileva-TonkovaE. Effectsofbiosurfactant-rhamnolipidonbacterialgrowthandproteinrelease. Екологично инженерство и опазване на околната среда, 2003, 3, 20-24.

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

Christova, N., B. Tuleva, Z. Lalchev, A. Jordanova, B. Jordanov. Rhamnolipid biosurfactants produced by Renibacterium salmoninarum27BN during growth on n-hexadecane. Z. Naturforsch., 2004, 59c, 70-74.

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

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

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

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

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

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

D. Karakashev, D. Galabova, N.Fuchedjieva, I.Simeonov . Effect of the Electron Acceptor Conditions o n the Proteolytic Activities of Bacteria Involved in Anaerobic Digestion . C.R.Acad.Bulg. Sci., 2005, 58, 3, 311-315.

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

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

Avramova, T., L. Stefanova, B. Angelova, S. Mutafov. Bacterial decolorization of Acid Orange 7 in the presence of ionic and non-ionic surfactants. Z. Naturforsch., 2006, 61 c.

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

Vasileva-Tonkova, E., D. Galabova, E. Stoimenova, Z. Lalchev. Characterization of bacterial isolates from industrial wastewater according to probable modes of hexadecane uptake. Microbiol. Research, 2006.DOI:10.1016/j.micres.2006.07.015

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

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