DEPARTMENT OF MICROBIAL BIOSYNTHESIS AND BIOTECHNOLOGIES

Mladenka Paunova Ilieva-Stoilova, DSc, ProfessorHead of DepartmentTel: (+359 32) 642 430

E-mail: mladenka.stoilova@gmail.com

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

STAFF

Bonka Tzvetkova, PhD, Associate Professor, bonka_ivanova@abv.bg

             

            

            

Alexander Ratkov, PhD, Associate Professor

             

            

            

Penka Alexieva, PhD, Associate Professor, aleks57@abv.bg

             

            

            

Veneta Ivanova, PhD, Associate Professor, venibiva@microbio.bas.bg

             

            

      

      

Emilina Simova, PhD, Associate Professor, lbpmbas @ yahoo . com

             

            

            

Tsonka Christozova, PhD, Associate Professor, tshristozova @ yahoo . com ; lbpmbas @ yahoo . com

             

            

            

Dora Beshkova, PhD, Associate Professor, beshkova@yahoo.com, lbpmbas@yahoo.com

             

            

            

Kostantza Pavlova, PhD, Associate Professor, konpavlova@yahoo.com; lbpmbas @ yahoo . com

             

            

            

Ginka Frengova, PhD, Associate Professor, : lbpmbas @ yahoo . com

             

            

            

Adriana Gousterova, PhD, Associate Professor, marine _ bg @ abv . bg

             

            

            

Atanas Pavlov, PhD, Associate Professor, at_pavlov@yahoo.com; lbpmbas@yahoo.com

             

            

            

Victoria Gesheva, PhD, Research Scientist, teteven@excite.com Vessela Raykovska, MS, Research ScientistLiliana Nacheva, MS, Research Scientist, lin 1@ abv . bg Dimka Tuneva, PhD, Research Assistant, lbpmbas @ yahoo . com Mariana Kolarova, MS, Research AssistantKrasya Aleksieva, MS, Research AssistantVelitchka Ivanova, MS, Research AssistantJulia Krusteva, MS, Research Assistant

Philip 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 Assistant, vasgeorgiev@gmail.com; lbpmbas@yahoo.com Svetla Kostadinova, Research Assistant, lbpmbas@yahoo.com Elka Genova, Laboratory Assistant lbpmbas@yahoo.com Stefka Vassileva, Laboratory AssistantVasilkaUsherova, Laboratory Assistant, lbpmbas@yahoo.com

MAIN RESEARCH TOPICS

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.).

MOST IMPORTANT ACHIEVEMENTS

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 PUBLICATIONS

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

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

Aleksieva, P., Nacheva, L., Panayotov A., Tchorbanov, B. Exopolysaccharides from fungal source using low carbohydrates solutions as fermentation substrates. Compt. Rend. Acad. Bulg. Sci. 2004, 57(2), 91-94.

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

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

Berkov, S., Pavlov, A., Ilieva, M., Burrus, M., Popov, S., Stanilova, M. GC/MS of alkaloids in Leucojum aestivum plants and their in vitro cultures. Phytochem Analysis 2005, 16, 98-103.

Berkov, S., Pavlov, A., Kovatcheva, P., Stanimirova, P., Philipov, S. Alkaloid Spectrum in Diploid and Tetraploid Hairy Root Cultures of Datura stramonium. Z. Naturforsh. 2003, 58c, 42-46.

Beshkova, D., Simova, E., Frengova, G., Simov, Z., Dimitrov, Zh. Production of volatile aroma compounds by kefir starter cultures. Int. Dairy J. 2003, 13(7), 529-535.

Beshkova, D.M., Simova, E.D., Frengova, G.I., Simov, Z., Spasov, Z. Effect of oxygen on batch yogurt cultures. World J. Microbiol. Biotechnol., 2002, 18, 3, 361-365.

Beshkova, D.., Simova, E., Simov, Z., Frengova, G., Spasov, Z. Pure cultures for making kefir. Food Microbiol. 2002, 19, 537-544.

Kovatcheva, E., Koleva, I., Ilieva, M., Pavlov, A., Mincheva, M., Konuslieva, M. Antioxidant activity of extracts from L. vera MM cell cultures. Food Chemistry 2001, 72, 295 – 300.

Frengova, G., Simova, E., Beshkova, D. Improvement of carotenoid-sinthesizing yeast by chemical mutagenesis. Z. Naturforsch. 2004, 59c, 99-103.

Frengova, G., Simova, E., Beshkova, D. Carotenoid production by lactosone-gative yeast co-cultivated with lactic acid bacteria in whey ultrafiltrate. Z. Naturforsch. 2003, 58c, 562-567.

Frengova, G., Simova, E., Beshkova, D. -Carotene-rich-protein preparation and exopolysaccharide production by Rhodotorula rubra GED8 grown with yogurt starter culture. Z. Naturforsch. 2006 (in press).

Frengova, G., Simova, E., Beshkova, D. Use of whey ultrafiltrate as a substrate for production of carotenoids by the yeast Rhodotorula rubra. Appl. Biochem. Biotechnol. 2004, 112, 3, 133-141.

Frengova, G., Simova, E., Beshkova, D., Simov, Z. Exopolysaccharides produ-ced by lactic acid bacteria of kefir grains. Z. Naturforsch. 2002, 57c, 805-810.

Georgiev, M., Kuzeva, S., Pavlov, A., Kovacheva, E., Ilieva, M. Enhanced Rosmarinic Acid Production by Lavandula vera MM Cell Suspension Culture through Elicitation with Vanadyl Sulphate. Z. Naturforsch. 2006 (in press).

Georgiev, M., Pavlov, A., Ilieva, M. Rosmarinic acid production by Lavandula vera MM cell suspension: the effect of temperature. Biotechnol. Letters 2004, 26, 855-856.

Gesheva, V. Formation and regeneration of Streptomyces hygroscopicus protoplasts. Сборник 10-ти конгрес по микробиология, 2002 (под печат).

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

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

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

Gocheva, J., Krumova, E., Slokoska, L., Gesheva, V., Angelova, M. Isolation of filamentous fungi from Antarctica. Compt. Rend. Acad. bulg. Sci. 2005, 58, 403-408.

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

Gotcheva V., M. Guo, E. Hristozova, Ts. Hristozova, Z. Roshkova, A. Angelov. Assessment of potential probiotic properties of Lactic acid bacteria and yeast strains. Food Biotechnol. 2002, 16(3), 211-225.

Gousterova, A., Braikova, D., Goshev, I., Christov, P., Tishinov, K., Vasileva-Tonkova, E., Haertlé, Т., Nedkov, P. Degradation of keratin and collagen containing wastes by newly isolated thermoactinomycetes or by alkaline hydrolysis . Lett. Appl. Microbiol. 2005, 40, 335-340.

Gushterova, A., Vasileva-Tonkova, E., Dimova, E., Nedkov, P., Haertle, T. Keratinase production by newly isolated Antarctic actinomycete strains. World J. Microbiol. Biotechnol. 2004, 21, 6-7, 831-834.

Gushterova, A., V. Ivanova, K. Aleksieva, M. Kolarova, B. Schlegel, U. Graefe. Taxonomic investigations of the Antarctic mesophilic strain 2BG, producer of secondary metabolites. J. Biotechnol. Biotechnological Equipment 2004, 18, 72-76.

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

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

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

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

Ilieva, M., Pavlov, A., Kovatcheva, E. 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 2002.

Ilieva, M., Pavlov, A., Bakalova, A. Phosphodiesterases production in an Aqueous Two-phase system by N. tabacum 1507 – Appl. Biochem. Biotechnol. 2001, 90(3), 261-272.

Kovatcheva, E., Koleva, I., Ilieva, M., Pavlov, A., Mincheva, M., Konuslieva, M. Antioxidant activity of extracts from L. vera MM cell cultures. Food Chemistry 2001, 72, 295 – 300.

Pavlov, A., Ilieva, M., Mincheva, M. Realease of rosmarinic acid by Lavandula vera MM cell suspension in two-phase culture systems. World J. Microbiol. Biotechnol. 2001, 17, 417-421.

Georgiev, V. Betalains biosynthesis by transformed root cultures from Beta vulgaris: influence of main components of the nutrient medium. Scientific works UFT, Plovdiv, Vol. LI 2004, (3), 183-189.

Pavlov, A., Georgiev, M., Georgiev, V., Gocheva, T., Tuneva, D., Ilieva, M., Burrus, M. Cultivation of Leucojum aestivum shoot cultures in bioreactor. Scientific Works UFT 2005, 52(2), 305-310.

Georgiev, M., Georgiev, V., Gocheva, T., Tuneva, D., Pavlov, A., Ilieva, M., Burrus, M. Optimization of nutrient medium composition for galanthamine biosynthesis by Leucojum aestivum shoot culture. Scientific Works UFT 2005 ,52(2), 311-315.

Ilieva, M., Pavlov, A., Bakalova, A. Phosphodiesterases production in an Aqueous Two-phase system by Nicotiana tabacum 1507. Appl. Biochem. Biotechnol. 2001, 90(3), 261-272.

Ilieva, M., Kratchanova, M., Pavlova, E., Dimova, T., Petrova, D., Pavlov, A., Mihneva, M. Polygalacturonase adnd pectinmethylesterase activities during growth of N. tabacum 1508 cell suspension. Scientific Works of Higher Institute of Food and Flavour Industries , XLVI: 2001, 185-190.

Ivanova, V., Oriol, M., Montes, M-J., Garcia, A., Guinea, J. Secondary Metabolites from a Streptomyces Strain Isolated from Livingston Island, Antarctica. Z. Naturforsch. 2001, 56c, 1-5.

Ivanova, V., Graefe, U., Schlegel, B., Kolarova, M., Aleksieva, K. Diphenilether and macrotriolides occurring in a fungal isolate from the antarctic lichen Neuropogon. Preparative Biochem. Biotechnol. 2006 (in press).

Ivanova, V., Graefe, U., Schlegel, R., Schlegel, B., Gushterova, A., Kolarova, M., Aleksieva, K. Isolation and structure elucidation of tyramine and indole alkaloids from antarctic strain. J. Biotechnol. Biotechnological Equipment 2003, 17, 128-133.

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

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

Kovacheva, E., Pashova, S., Georgiev, M., Angelova, M., Ilieva, M. Radical scavenging properties of Lavandula vera MM cell culture extracts and preparations. Z. Naturforsch. C 2006 (in press)

Georgiev, M., Kovacheva, E., Marcheva, N., Ilieva, M. Purification of rosmarinic acid extracts from Lavandula vera MM cell biomass. Food Chemistry 2006, 94 (1), 111-114.

Maciuk, M., Georgiev, A., Toribo, M., Zeches-Hanrot, Ilieva, M., Nuzillard, J-M., Renault, J-H. Purification of rosmarinic acid by strong ion-exchange centrifugal partition chromatography. J. Liquid Chromatography and Related Technologies 2005, 28, 1947-1957.

Nedeva, T., Petrova, V., Hristozova, Ts., Kujumdzieva, A. A modified procedure for isolation of yeast mitochondrial DNA. Z. Naturforsh. 2002, 57 C, 960-961.

Nicolova, Kr., Panchev, I., Sajnov, S., Pavlova, K. Optical characteristics of biopolymer films from gelatin, mannan and glucomannan. Proc. of SPIE 2005 (in press).

Nustorova, М., Braikova, D., Gousterova, A., Vasileva-Tonkova, E., Nedkov, P. Chemical, microbiological and plant analysis of soil fertilized with alkaline hydrolysate of sheep’s wool waste. World J. Microbiol. Biotechnol. 2005 (in press).

Pavlov, A., Bley, Th. Betalains biosynthesis by Beta vulgaris hairy root culture in a temporary immersion cultivation system. Process Biochemistry 2006, 41(4), 848-852.

Pavlov, A., Georgiev, M., Ilieva, M. Production of rosmarinic acid by Lavandula vera MM cell suspension in bioreactor: Effect of dissolved oxygen concentration and agitation. Word J. Microbiol. Biotechnol. 2005, 21, 389-392.

Pavlov, A, Georgiev, M, Panchev, I, Ilieva, M. Optimization of rosmarinic acid production by Lavandula vera MM plant cell suspension in a laboratory bioreactor. Biotechnology Progress 2005, 21, 394-396.

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

Pavlov, A, Georgiev, V, Kovatcheva, P. Reletionship between type and age of inoculum and betalains biosynthesis by B. vulgaris hairy root culture, Biotechnol. Letter 2003, 25 (4), 307-309.

Pavlov, A, Kovatcheva, P, Georgiev, V, Koleva, I, Ilieva, M. Biosynthesis and Radical Scavenging Activity of Betalains during the Cultivation of Red Beet (Beta vulgaris) Hairy Root Cultures Z. Naturforschung 2002, 57c, 640-644.

Pavlov, A., Kovatcheva, P., Tuneva, D., Ilieva, M., Bley, Th. Radical scavenging activity and Stability of Betalains from Beta vulgaris hairy root culture in Simulated Conditions of Human Gastrointestinal Tract. Plant Food for Human Nutrition 2005, 60, 43-47.

Pavlov, A., Ilieva, M., Mincheva, M. Release of rosmarinic acid by Lavandula vera MM cell suspension in two- phase culture systems. World J. Microbiol. Biotechnol. 2001, 17, 417-421.

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

Pavlov, A., Werner, S., Ilieva, M., Bley, Th. Characteristuc of Helianthus annuus plant cell culture as a producer of immunologically active exopolysaccharides. Engineering in Life Sciences 2005, 5(3), 280-283.

Pavlova, K., Grigorova, D., Hristozova, T., Angelov, A. Yeast strains from Livingston Island, Antarctica. Folia Microbiol. 2001, 46(5), 397-401.

Pavlova, K., Angelova, G., Savova, I., Grigorova, D., Kupenov, L. Studies of Antarctic yeast strains for -glucosidase production. World J. Microbiol. Biotechnol. 2002,18, 569-573.

Pavlova, K., Panchev, I., Hristozova, Ts.. Physoco-chemical characterization of exomannan by Rhodotorula aheniorum MC. World J. Microbiol. Biotechnol. 2005, 21, 279-283.

Pavlova, К., Koleva, L., Kratchanova, M., Panchev, I. Production and charactereization of an exopolysaccharide by yeast. World J Microbiol. Biotechnol. 2004, 20(4), 435-440.

Rachev, R., Gesheva, V., Tewfike, T., Bojkova, S., Ztvetkova, R. A new antibiotic, TH818 and its properties. Biotechnol. Appl. Biochem. 2003, 37, 1-6.

Simov, Zh.I., Simova, E.D., Beshkova, D.M. Impact of two starter cultures on proteolysis in Kashkaval cheese. World J. Microbiol. Biotechnol. 2005, DOI: 10.1007/s11274-005-9012-5.

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

Simova, E., Frengova, G., Beshkova, D. Synthesis of carotenoids by Rhodoto-rula rubra GED8 co-cultured with yogurt starter cultures in whey ultrafiltrate. J. Ind. Microbiol. Biotechnol. 2004, 31, 115-121.

Simova, E., Angelov A., Beshkova D., Frengova G., Hristozova T., Spasov Z. Microorganisms present in kefir grans. J. Ind. Microbiol. Biotechnol. 2002, 28, 1 – 6.

Simova, E., Frengova, G., Beshkova, D. Effect of aeration on the production of carotenoid pigments by Rhodotorula rubra – Lactobacillus casei subsp.casei co-cultures in whey ultrafiltrate. Z. Naturforsch., 2003, 58c, 225-229.

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

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

Simova, E.D., Beshkova, D.M., Simov, Zh.I. Peptidolytic profiles of starter and nonstarter lactic acid bacteria for manufacturing fermented milks and cheeses. Food Microbiol. 2005 (in press).

Simova, E.D., Simov, Zh.I., Beshkova, D.M. Contribution of starter cocci and nonstarter lactobacilli to proteolysis of Kashkaval cheese. Int. J. Food Microbiol. 2005 (in press).

Tsiroulnikov K., Rezai, H, Bonch-Osmolovskaya, El., Nedkov, P., Gousterova, A., Cueff, V., Godfrory, A., Barbier, G., Ois Meatro, F., Chobert, J.M., Clayette, P., Dormont, D., Grosclaude, J., Hheartle, T. Hydrolysis of the Amyloid Prion Protein and Nonpathogenic Meat and Bone Meal by Anaerobic Thermophilic Prokaryotes and Streptomyces Subspecies. J. Agric. Food Chem. 2004, 52, 6353-6360.

Tzvetkova, B., Hristozova, Ts., Angelov, A., Paskaleva, D. Effect of furfural on the growth of lactose-utilizing Candida blankii 35. World J. Microbiol. Biotechnol. 2004, 20, 219-233.

Vasileva- Tonkova, E., Gesheva, V. Glycolipids produced by antarctic Nocardiodes sp. during growth on n- paraffin. Process Biochem. 2005, 40(7), 2387-2391.

Vassileva-Tonkova, E., Gesheva, V. Potential for biodegradation of hydrocarbons by microorganisms from antarctic soils. Z. Naturforsch. 2004, 59c, 140-145.

Zlatanov, M., Pavlova, K., Grigorova, D. Lipid Composition of Some Yeast Strains from Livingston, Antarctica. Folia Microbiol., 2001, 46(5), 402-406.