Adaptive and biotechnological potential of Streptomyces strains isolated from adverse biotopes
Abstract
Background. Streptomyces spp. from adverse biotopes are characterized by broad adaptive capacities, unique metabolism, and biotechnological potential. In this study, Streptomyces strains isolated from adverse habitats were investigated through phylogenetic analysis, bioactivity assays, and evaluation of their adaptive and biotechnological potential. Materials and Methods. Genetic methods (DNA extraction and 16S rRNA gene sequencing), microbiological methods (agar block confrontation assay for antagonism; cultivation on nutrient media supplemented with heavy metals to assess metal resistance; Kirby–Bauer disk diffusion method for antibiotic susceptibility testing), biochemical methods (enzymatic activity assays and carbon source utilization), and bioinformatic tools (molecular phylogeny in MEGA12.1.1; genome annotation using RAST and DFAST) were employed. Results. Phylogenetic analysis revealed close relatedness among strains 89, 34, and SK7, which clustered into a single clade of the phylogenetic tree. They exhibited moderate antifungal activity. Among them, strain 89 inhibited fungi of the genera Fusarium and Rhizoctonia. Chromium and iron were the least toxic to all strains; zinc and cobalt showed moderate toxicity, while nickel and copper were the most toxic. Growth inhibition occurred at 25 mg/L of nickel and 50 mg/L of copper; only strain 89 tolerated 100 mg/L of copper. Strain 89 exhibited lipase, amylase, and cellulase activities, along with the ability to hydrolyze casein and metabolize glycerol, mannitol, and diverse sugars, thereby underscoring its potential for the degradation of organic residues. Conclusions. S. anulatus 89 possesses broad adaptive and biotechnological potential and inhibits some phytopathogens.