LABORATORY OF EXTREMOPHILIC MICROORGANISMS

Assist. Prof. Ivanka Boyadzhieva, PhD

Tel.: +359 2 979 31 76

E-mail: petrovaim@abv.bg

 

STAFF:

 

Assoc. Prof. Nadja Radchenkova, PhD 

Tel.: +359 2 979 31 83

E-mail: nstoicheva@yahoo.com  

 

Assist. Prof. Miroslava Atanassova, PhD

Tel: +359 2 979 31 75

E-mail: mira_atanassova@yahoo.com  

 

Assist. Nikolina Atanassova

Tel: +359 2 979 31 83

E-mail: ninka_at@yahoo.com  

 

Assist. Nikolay Krumov

Tel: +359 2 979 31 75

E-mail: npkrumov@microbio.bas.bg

 

Kaloyan Berberov, microbiologist

Tel: +359 2 979 31 75

 

 

CURRENT RESEARCH TOPICS:

 

• Biodiversity of extremophilic microorganisms – bacteria and archaea. The characterization of the microbial diversity in extreme niches is carried out by applying modern and classical molecular and microbiological methods. The structure of a number of microbial communities is characterized; the presence of unknown microorganisms that cannot be attributed to previously identified phylogenetic units has been identified. Three new species (Anoxybacillus rupiensis, A. bogrovensis and Myroides guanonis) have been described and validly recognized.

• Biosynthetic capacity of extreophilic microorganisms for synthesis of biotechnologically valuable enzymes. These organisms are recognized as industrially important in the production of thermostable enzymes. Producers of various hydrolases and lyases have been isolated: pullulanase, inulinase, pectinase, xylanase, lipase, amylase, cyclodextrin glucone transferase, glucosidase and others. The first and still the only thermostable gelan lyase was isolated and characterized in the laboratory. The regulation of enzyme synthesis in periodic and continuous cultures has been studied. Optimal schemes for purification of enzymes with maximum yield have been created. The substrate specificities of the enzymes, the physicochemical parameters of action, the kinetic constants of the enzymatic reactions, the influence of various inhibitors, detergents and organic solvents on the enzyme activities were studied.

• Biosynthesis of exopolysaccharides (EPZ) from extreophilic microorganisms – thermophiles and halophiles. The unusual metabolic pathways observed in some extrophiles arouse interest in extremophilic microorganisms as potential producers of EPZ with new and unusual properties and functional activity under extreme conditions. Thermophilic and halophilic microorganisms and their EPZ show several biotechnological advantages, such as lack of pathogenicity, unusual stability of polysaccharides. A polysaccharide with very high biological activity was isolated from a thermophilic strain of Geobacillus tepidamans. New EPZs were isolated from the Aeribacillus pallidus strain. The high viscosity, emulsifying, water-retaining and foaming ability of EPZ, synthesized by the halophilic bacterium Chromochalobacter canadensis, favor its application in the cosmetics industry. It also showed good biocompatibility with human keratinocyte cells (HaCaT).

• The excellent characteristics and advantages of plastics contribute to economic growth, which favors their widespread accumulation in the environment in huge quantities. As physical and chemical methods create a number of environmental problems, the need for biodegradation of plastic waste is obvious, but still not effective enough. Extremophilic microorganisms synthesize unusual metabolites, including a wide range of biopolymers harmful to humans. However, little is known about the ability of extremophilic microorganisms to degrade synthetic polymer substrates. Based on the experience in the laboratory Extremophilic bacteria and the laboratory Morphology of microorganisms and electron microscopy, studies have been launched on the composition of thermophilic and halophilic microbial communities, developing in environments with different types of plastics as a carbon source. Electron microscopic studies of changes in the structure of plastics as a result of the development of biofilms on their surface. Hydrolase activities (esterase and proetase) of both communities and isolated single strains are also studied.

 

PROJECTS:

 

• “Degradation of plastic waste from extremophilic prokaryotes”. Contract KP-06-Russia-17 (2019-2021), funded by the National Research Fund under Bulgaria-Russia Bilateral Cooperation Program. Head of the Bulgarian team: Prof. M. Kambourova, IMikB, BAS; head of the Russian team: Prof. Elizaveta Bonch-Osmolovskaya.

• “Production and functional properties of an exopolymer synthesized by a halophilic bacterium Chromohalobacter canadensis 28” (2019-2021). International cooperation in the framework of inter-academic agreements with Marmara University, Istanbul, Turkey. Head of Bulgarian team: Prof. M. Kambourova, IMikB, BAS; head of Turkish team: Prof. Ebru Toksoy Oner

• „Продукция и функционални свойства на екзополимер, синтезиран от халофилната бактерия Chromohalobacter canadensis 28“ (2019-2021). Международно сътрудничество в рамките на междуакадемични договори и споразумения с Мармара Университет, Истанбул, Турция. Ръководител на българския екип: Проф. М. Камбурова, ИМикБ, БАН; ръководител на турския екип: Prof. Ebru Toksoy Oner

• "Isolation and characterization of thermostable pectin-degrading enzymes from extremophilic microorganisms" (2018-2021). International cooperation with in the framework of inter-academic contracts and agreements with the Institute of Biomolecular Chemistry, SNR, Naples, Italy. Head of the Bulgarian team: Prof. M. Kamburova, IMikB, BAS; head of the Italian team: Dr. Annarita Poli.
• “Biodiversity of halophilic microorganisms isolated from Bulgarian salt niches and their potential for synthesis of expolysaccharides”. Contract B-02 / 26 (2014-2020), funded by the National Research Fund. Project leader: Prof. M. Kambourova.
• „Diversity and biotechnological potential of extreme and hyper thermophilic microorganisms from Bulgarian hot springs. Contract DFNP 17-39 / 2017, Program for support of young scientists and doctoral students. Project leader: doctoral student Nikoleta Boteva; Scientific consultant: Prof. M. Kambourova

 

PUBLICATIONS:

 

• Radchenkova, N., Boyadzhieva, I., Hasköylü, M.E., Atanasova, N., Yaşar Yıldız, S., Kuncheva, M.J., Panchev, I., Kisov, H., Vassilev, S., Toksoy Oner, E., Kambourova, M.S. (2020) High bioreactor production and emulsifying activity of an unusual exopolymer by Chromohalobacter canadensis 28. Eng. Life Sci., v. 20 (8), DOI: 10.1002/elsc.202000012
• Kambourova, M. (2019) Chapter 1. Exploring the Capacity of Halophilic Microorgansisms to Synthesize Exopolysaccharides with Interesting Properties. In: Microbial Exopolysaccharides: Current Research and Developments (Ed. Ateş Duru, Ö.), Caister Academic Press, 1-24. DOI: 10.21775/9781912530267.01
• Erginer Hasköylü, M., Kambourova, M., Toksoy Öner, E. (2019) Chapter 8. Fructans as Natural, Bioactive Cosmeceutical Ingredients. In: Microbial Exopolysaccharides: Current Research and Developments (Ed. Ateş Duru, Ö.), Caister Academic Press, , ISBN:978-1-912530-27-7, DOI: 10.21775/9781912530267.08, 183-216
• Abbamondi, G. R., Kambourova, M., Poli, A. (2019) Chapter 4. Quorum Sensing in Extremophiles. In: Quorum Sensing Molecular Mechanism and Biotechnological Application (Ed. Tommonaro, G), Academic Press, 97-123. DOI: 10.1016/B978-0-12-814905-8.00004-6
• Radchenkova, N., Boyadzhieva, I., Atanasova, N., Poli, A., Finore, I., Di Donato, P., Nicolaus, B., Panchev, I., Kuncheva, M., Kambourova, M. (2018) Extracellular polymer substance synthesized by a halophilic bacterium Chromohalobacter canadensis 28. Appl Microbiol Biotechnol., 102, 11, 4937-4949. DOI: 10.1007/s00253-018-8901-0
• Boyadzhieva, I., Radchenkova, N, Tomova, I., Kambourova, M., Poli, A., Vasileva-Tonkova, E. (2018) Diversity of heterotrophic halophilic bacteria isolated from coastal solar salterns, Bulgaria and their ability to synthesize bioactive molecules with biotechnological impact. Microbiology, 87, 4, 519-528. DOI: 10.1134/S0026261718040033
• Boteva, N., Kambourova M. (2018) Thermophiles and their exploration for thermostable enzyme production. In: Extremophiles in Eurasian Ecosystems: Ecology, Diversity, and Applications (Eds. Egamberdieva, D., Birkeland, N.-K., Panosyan H., Li W.-J.). Springer Nature Singapore Ltd., Springer, Singapore, 167-186. DOI: 0.1007/978-981-13-0329-6_6
• Kambourova M. (2018) Thermostable enzymes and polysaccharides produced by thermophilic bacteria isolated from Bulgarian hot springs. Engineering in Life Sciences, 18, Wiley Online Library, 758-767. DOI: 10.1002/elsc.201800022
• Kambourova, M., Tomova, I., Boyadzhieva, I., Radchenkova, N., Vasileva-Tonkova, E. (2017) Phylogenetic analysis of the bacterial community in a crystallizer pond, Pomorie salterns, Bulgaria. Biotechnology and Biotechnological Equipment, 31, 2, 325-332. DOI: 10.1080/13102818.2016.1265900
• Kambourova, M. (2017) Recent Advances in Extremophilic α-Amylases. In: Extremophilic Enzymatic Processing of Lignocellulosic Feedstocks to Bioenergy (Eds. Sani, K. & Krishnaraj, R.N.), Springer Nature, 99-113. DOI: 10.1007/978-3-319-54684-1
• Kambourova, M., Tomova, I., Boyadzhieva, I., Radchenkova, N., Vasileva-Tonkova, E. (2016) Unusually High Archaeal Diversity in a Crystallizer Pond, Pomorie Salterns, Bulgaria, Revealed by Phylogenetic Analysis. Archaea, 2016, Article ID 7459679, DOI:10.1155/2016/7459679
• Kambourova, M., Radchenkova, N., Tomova, I., Bojadjieva, I. (2016) Thermophiles as a Promising Source of Exopolysaccharides with Interesting Properties. In: Biotechnology of Extremophiles (Ed. Rampelotto, P.H.) Springer, 117-139. DOI: 10.1007/978-3-319-13521-2