Zhechko Dimitrov

Prof. Dr. Zhechko Dimitrov


Research Focus & Metrics

Academic Career Length

22Years (2005-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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17 July 2022 in Journal of Fungi
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Journal Article
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GAGalena Angelova
Galena Angelova
Mariya BrazkovaMariya Brazkova
Mariya Brazkova
Dasha MihaylovaDasha Mihaylova
Dasha Mihaylova
ASAnton Slavov
Anton Slavov
Nadezhda PetkovaNadezhda Petkova
Nadezhda Petkova
Albert KrastanovAlbert Krastanov
Albert Krastanov
The aim of this study is to characterize the bioactivity of mycelial biomass and crude exopolysaccharides (EPS) produced by Trametes versicolor NBIMCC 8939 and to reveal its nutraceutical potential. The EPS (1.58 g/L) were isolated from a culture broth. The macrofungal biomass was rich in protein, insoluble dietary fibers and glucans. The amino acid composition of the biomass was analyzed and 18 amino acids were detected. Three mycelial biomass extracts were prepared and the highest total polyphenol content (16.11 ± 0.14 mg GAE/g DW) and the total flavonoid content (5.15 ± 0.03 mg QE/g DW) were found in the water extract. The results indicated that the obtained EPS were heteropolysaccharides with glucose as the main building monosaccharide and minor amounts of mannose, xylose, galactose, fucose and glucuronic acid. Fourier Transform Infrared Spectroscopy (FTIR) confirmed the complex structure of the crude EPS. Five probiotic lactic acid bacteria strains were used for the determination of the prebiotic effect of the crude EPS. The anti-inflammatory potential was tested in vitro using cell line HT-29. The significant decrease of IL-1 and IL-8 and increase of TGF-beta expression revealed anti-inflammatory potential of the crude exopolysaccharides from T. versicolor.


9 March 2025 in Crystals
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Journal Article
Open access
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Ignat IgnatovIgnat Ignatov
Ignat Ignatov
YMYordan G. Marinov
Yordan G. Marinov
PVPaunka Vassileva
Paunka Vassileva
TPTeodora Petrova Popova
Teodora Petrova Popova
GGGeorgi Gluhchev
Georgi Gluhchev
IGIrina Marinova Gotova
Irina Marinova Gotova
This study explores the structural and chemical interactions between glacial water, ice Ih, and hydration clusters of divalent cations (Ca2⁺ and Mg2⁺). Ice Ih, with its hexagonal lattice and tetrahedral bonding network, is incompatible with the hydration shells of Ca2⁺ and Mg2⁺, which adopt octahedral geometries in aqueous solutions. During freezing, these hydration clusters become disordered, causing distortions in the ice structure. Slow freezing reduces these distortions, while rapid freezing traps ions in amorphous regions, preventing proper alignment of hydration clusters. Through advanced techniques such as chemical and isotopic analysis, computational modeling, and electrical impedance spectroscopy, this study examines ion exclusion mechanisms and water-clustering behaviors. The results show that both ions are largely excluded from the solid phase during freezing, with Mg2⁺ exhibiting stronger exclusion due to its smaller ionic radius and greater hydration energy. This study also highlights the role of sediments in modulating ion patterns in glacial ice. This work deepens our understanding of ion–ice interactions, offering insights for cryochemistry, hydrology, and environmental science. The integration of experimental and computational methods provides new perspectives on divalent cations’ role in modifying ice’s crystalline structure and explains isotopic variability in glacial waters.

29 April 2025 in Beverages
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TTTeodora Todorova
Teodora Todorova
KBKrasimir Boyadzhiev
Krasimir Boyadzhiev
Ignat IgnatovIgnat Ignatov
Ignat Ignatov
TPTeodora Petrova Popova
Teodora Petrova Popova
ZDZhechko Dimitrov
Zhechko Dimitrov
YMYordan G. Marinov
Yordan G. Marinov
The present study aimed to analyze the physicochemical properties and biological activity of an L-malic acid descaler. The treated water with L-malic acid descaler complies with EU Directive No. 2020/2184 for the quality of water intended for human consumption. The L-malic acid descaler contains L-malic acid as the active component, while polyethylene and activated charcoal function as structural and absorbent materials, respectively. The composition was analyzed in a licensed laboratory using Chemical Abstracts Service Number (CAS) and European List of Notified Chemical Substances (EINECS) standards. Fourier Transform Infrared (FT-IR) analysis confirmed the presence of hydroxyl (–OH), carbonyl (C=O), and carboxyl (–COOH) groups in L-malic acid descaler, which are connected with proton-donating ability, and redox activity. The biological activity was evaluated using Saccharomyces cerevisiae as a model system. The role of the YAP1 transcription factor, a key regulator of oxidative stress defense mechanisms, was also examined. The detrimental effects on a cellular level were induced by the well-known mutagen—methyl methanesulfonate (MMS). Our data revealed that yeast cells treated with such water decrease the MMS-induced superoxide anions (3.5-fold), total glutathione lipid peroxidation (1.5-fold), and total glutathione (3-fold) and increase cell survival (2-fold). In conclusion, water treated with L-malic acid descaler possesses antioxidant effects in yeast-cell-based tests, independent of YAP1 transcription factor activity. This study provides preliminary evidence that L-malic acid, when dissolved in water, significantly reduced MMS-induced superoxide anions, one of the biomarkers contributing to the genotoxic and carcinogenic effects of MMS.