Antimicrobial activity of actinobacteria isolated from water column and biofilm of the lake system La Izvor (Republic of Moldova)

Abstract

The paper deals with the research results of studies of antimicrobial activity of actinobacteria isolated from water column and biofilm of the lake system La Izvor (Republic of Moldova). Antimicrobial activity of 34 strains of actinobacteria (Actinomadura, Actinoplanes, Frankia, Geodermatophilus, Micromonospora, Nocardia, Rhodococcus, Streptomyces) was determined by the disk diffusion method, as test cultures served pathogenic bacteria and fungi which are common on territory of Republic of Moldova and cause diseases of crops. According to results of antibacterial activity, the diameter of growth inhibition zones varied from 9.0 to 16.3 mm (active strains are represented by genera Streptomyces and Micromonospora). The best results of antifungal activity were noted by strains of genera Actinomadura, Actinoplanes, Micromonospora, and Streptomyces. Diameter of growth inhibition zones of such phytopathogenic fungi as Alternaria alternata, Aspergillus niger, and Fusarium solani varied within 20.7-24.0 mm. New strains of Actinoplanes, Actinomadura, Micromonospora, and Streptomyces will replenish the National Collection of Non-pathogenic Microorganisms of the Institute of Microbiology and Biotechnology.