Browsing by Author "Gospodinova D."

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    Comparative Study of the Marinobacter hydrocarbonoclasticus Biofilm Formation on Antioxidants Containing Siloxane Composite Coatings
    (2022-07-01) Vladkova T.G.; Monov D.M.; Akuzov D.T.; Ivanova I.A.; Gospodinova D.
    No systematic study of antioxidant containing coatings and their anti-biofilm action has been reported so far. The utilization of antioxidants in protective coatings to inhibit marine biofilm formation is a current challenge. The aim of this preliminary study was to prepare, characterize and compare the efficiency of low adhesive siloxane composite coatings equally loaded with different antioxidants against mono-species biofilms formation. Most often participating in the marine bio-films formation, Marinobacter hydrocarbonoclasticus was the test bacterium. Both the biofilm covered surface area (BCSA) and corrected total cell fluorescence (CTCF) (by fluorescent microscopy) were selected as the parameters for quantification of the biofilm after 1 h and 4 h incubation. Differing extents of altered surface characteristics (physical-chemical; physical-mechanical) and the specific affection of M. hydrocarbonoclasticus biofilm formation in both reduction and stimulation, were found in the studied antioxidant containing coatings, depending on the chemical nature of the used antioxidant. It was concluded that not all antioxidants reduce mono-species biofilm formation; an-tioxidant chemical reactivity stipulates the formation of an altered vulcanization network of the siloxane composites and thus microbial adhesion which influences the surface characteristics of the vulcanized coatings; and low surface energy combined with a low indentation elastic modulus are probably pre-requisites of low microbial adhesion.
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    Recent Progress in Antioxidant Active Substances from Marine Biota
    (2022-03-01) Vladkova T.; Georgieva N.; Staneva A.; Gospodinova D.
    Background: The well-recognized but not fully explored antioxidant activity of marinebiota-derived, biologically active substances has led to interest in their study as substitutes of antibiotics, antiaging agents, anticancer and antiviral drugs, and others. The aim of this review is to present the current state of the art of marine-biota-derived antioxidants to give some ideas for potential industrial applications. Methods: This review is an update for the last 5 years on the marine sources of natural antioxidants, different classes antioxidant compounds, and current derivation biotechnologies. Results: New marine sources of antioxidants, including byproducts and wastes, are presented, along with new antioxidant substances and derivation approaches. Conclusions: The interest in high-value antioxidants from marine biota continues. Natural substances combining antioxidant and antimicrobial action are of particular interest because of the increasing microbial resistance to antibiotic treatments. New antioxidant substances are discovered, along with those extracted from marine biota collected in other locations. Byproducts and wastes provide a valuable source of antioxidant substances. The application of optimized non-conventional derivation approaches is expected to allow the intensification of the production and improvement in the quality of the derived substances. The ability to obtain safe, high-value products is of key importance for potential industrialization.