getpdf  NLM-PubMed-Logo  https://doi.org/10.17113/ftb.56.04.18.5905

 

Isolation, Characterization and Amino Acid Composition of a Bacteriocin Produced by Bacillus methylotrophicus Strain BM47


Yulian Tumbarski1*orcid tiny, Ivelina Deseva2orcid tiny, Dasha Mihaylova3orcid tiny, Magdalena Stoyanova2orcid tiny, Lutsian Krastev2orcid tiny, Radosveta Nikolova1orcid tiny, Velichka Yanakieva1orcid tiny and Ivan Ivanov4orcid tiny


1Department of Microbiology, University of Food Technologies, 26, Maritsa Blvd., 4002 Plovdiv, Bulgaria
2Department of Analytical Chemistry and Physicochemistry, University of Food Technologies, 26, Maritsa Blvd., 4002 Plovdiv, Bulgaria
3Department of Biotechnology, University of Food Technologies, 26, Maritsa Blvd., 4002 Plovdiv, Bulgaria
4Department of Organic Chemistry and Inorganic Chemistry, University of Food Technologies, 26, Maritsa Blvd., 4002 Plovdiv, Bulgaria


Article history:
Received: 19 June 2018
Accepted: 9 October 2018
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Key words:
Bacillus methylotrophicus, bacteriocin, antimicrobial activity, amino acid composition


Summary:
Members of the bacterial genus Bacillus are known as producers of a broad spectrum of antibiotic compounds of proteinaceous nature that possess inhibitory activity against different saprophytic and pathogenic microorganisms. In the current research, a peptide synthesized by Bacillus methylotrophicus strain BM47, previously isolated from a natural thermal spring in Bulgaria, was identified and characterized as a bacteriocin. In vitro antimicrobial screening of the crude bacteriocin substance of B. methylotrophicus BM47 showed activity against the plant pathogenic fungi Fusarium moniliforme, Aspergillus awamori, Penicillium sp., Aspergillus niger and Gram-negative bacterium Pseudomonas aeruginosa. The antimicrobial activity of the crude bacteriocin substance was partially inhibited by the enzymes trypsin, Alcalase®, Savinase®, proteinase K, papain and Esperase®, while catalase was not effective. The crude bacteriocin substance was relatively pH resistant, but sensitive to the action of heat and most organic solvents and detergents tested. To obtain the active protein fractions, crude bacteriocin substance was purified by fast protein liquid chromatography (FPLC) using a strong anion exchange column. Tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis demonstrated that the purified bacteriocin had molecular mass of 19 578 Da. The amino acid analysis performed by high-performance liquid chromatography (HPLC) revealed that the isolated bacteriocin consisted of 17 types of amino acids, with the highest mol fraction expressed as percent of serine (29.3), valine (10.3), alanine (9.8) and tyrosine (7.1).



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