Antifungal activity of lactobacilli isolated from Armenian dairy products: an effective strain and its probable nature

Abstract

Different strains of lactobacilli isolated from Armenian dairy products (matsoun, sour cream and different types of cheeses), were studied for antifungal activity. Lactobacillus rhamnosus MDC 9661 strain was shown to have inhibitory activity against Penicillium aurantioviolaceum and Mucor plumbeus growth. Bacterial cell-free supernatant didn’t show antifungal activity. The L. rhamnosus antifungal activity was stable to the wide range of pH from 3 to 10. This activity was high after treatment with both low temperature (− 30 °C) and lysozyme and with ultrasound. However, it was sensitive to high temperature from 45 to 80 °C and proteolytic enzymes. The results suggest the proteinaceous nature of L. rhamnosus antifungal activity associated with bacterial cell wall. L. rhamnosus MDC 9661 could be recommended as a starter for production of dairy products, functional food and preserving strain in food production.

Comparative analysis of the effect of Ca and Mg ions on antibacterial activity of lactic acid bacteria isolates and their associations depending on cultivation conditions

“…The proteinaceous nature of their antibacterial components had been shown. The bacteriocineous nature of antibacterial components synthesized by LAB associations should be confirmed (Movsesyan et al 2010; Bazukyan et al 2018). So we can only speculate that in the combinations they synthesized some antibacterial components with proteinaceous nature, too.…”

Antifungal and antibacterial effects of newly created lactic acid bacteria associations depending on cultivation media and duration of cultivation

“…To determine the antifungal activity, the six most active LAB strains were selected, and from these strains 15 different combinations were created according to Bazukyan et al [19] and Matevosyan et al [20]. The antifungal activity of E. durans was not studied, since it is the reference strain from INRA (Nantes, France), the antifungal activity of which was shown by Ahmadova et al [22].…”

“…The suspension of fungal/molds spores (the amount was 10 4 per ml) was dropwise applied on the surface of media after 48 h LAB cultivation. The suspensions of fungal spores were prepared according to Bazukyan et al [19]. The antifungal activity was detected in the absence of fungal/molds growth on the surface of the medium (quantitative test).…”

Profiling of Potential Antibacterial Compounds of Lactic Acid Bacteria against Extremely Drug Resistant (XDR) Acinetobacter baumannii

“…The mechanisms of action of antibacterial activity against other pathogens such as Shigella sonnei was due to the production of organic acids and macromolecules involved in inhibition [2]. Studies have also shown that lactic acid bacteria have a vast amount of bioactive compounds that are beneficial as antifungal [3], antibiotic-resistant uropathogens [3], and other human pathogenic bacteria [4], in addition to other potential uses such as anti-cancer, anti-hypertensive, anti-thrombotic, lowering of cholesterol [5], anti-oxidant, and immunomodulation from food proteins [6] in the receptors of the gut epithelium [7]. Further assessment and classification of these bacteria as potential probiotic typically requires in vitro and in vivo study.…”