title: Antifungal activity and identification of Lactobacilli, isolated from traditional dairy product "katak".
abstract: Filamentous moulds are the main spoilage microorganisms, responsible for significant economic losses and several healthy risks in human food chain. The lactic acid bacteria (LAB), especially lactobacilli could be a natural antagonist of these dangerous organisms. In Bulgaria, a very limited data exists on the antifungal activity of LAB microbiota of fermented dairy products. In the present study, four active strains were isolated from traditional fermented curd/yogurt-like product "katak", produced in Bulgaria from centuries. The new isolates KR3, KR4, KR51 and KR53 were identified by API 50 CH biochemical test and different molecular methods (species-specific PCR, RAPD-PCR and 16S rDNA sequence analysis) as Lactobacillus brevis. According to our knowledge, this is the first data on the molecular characterization of the Lactobacillus microbiota of "katak". A broad spectrum of antifungal activity of the four L. brevis KR strains against test-cultures representatives of carcinogenic, toxigenic, deteriorative and allergenic fungi from the genera Aspergillus, Fusarium, Penicillium and Trichoderma was estimated. Strains L. brevis KR3, KR4 and KR51 completely suppress the growth of Penicillium claviforme, Aspergillus awamori and Aspergillus niger. With regard to Aspergillus flavus and Trichoderma viride, a lower and strain-specific inhibitory activity was observed. The antifungal activity of our new L. brevis isolates seems to be a promising advantage of these four strains, suggesting their potential applications in different food technologies as bio-preservative agents against moulds.
authors.affiliation: Department of General Microbiology, The Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences, 26, Acad. G. Bontchev Str., 1113 Sofia, Bulgaria.
authors.forename: Rositsa
authors.initials: R
authors.lastname: Tropcheva
authors.affiliation: Department of Biotechnology, Faculty of Biology, Sofia University St. Kliment Ohridski, 8, Dragan Tsankov Blvd., 1164 Sofia, Bulgaria.
authors.forename: Dilyana
authors.initials: D
authors.lastname: Nikolova
authors.affiliation: Department of Biotechnology, Faculty of Biology, Sofia University St. Kliment Ohridski, 8, Dragan Tsankov Blvd., 1164 Sofia, Bulgaria.
authors.forename: Yana
authors.initials: Y
authors.lastname: Evstatieva
authors.affiliation: Department of General Microbiology, The Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences, 26, Acad. G. Bontchev Str., 1113 Sofia, Bulgaria. Electronic address: std@microbio.bas.bg.
authors.forename: Svetla
authors.initials: S
authors.lastname: Danova
mesh_terms: D000898:Antibiosis; D015373:Bacterial Typing Techniques; D002031:Bulgaria; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D003611:Dairy Products / Q000382:microbiology*; D005658:Fungi / Q000254:growth & development*; D006801:Humans; D007778:Lactobacillus / Q000302:isolation & purification* / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D019105:Random Amplified Polymorphic DNA Technique; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S
keywords: Antifungal activity; Aspergillus; Fusarium; Katak; Lactobacillus brevis; Penicillium; Trichoderma