Actinomycetes from sediments: Potential for bioactive substance production and crude oil degradation

This study analyzes sediment samples from the river in Bejaia (Algeria), and then to isolate and screen actinomycetes strains producing biologically active substances and degrading crude oil. Physicochemical studies were performed on sediment samples (SM, SE, and SS). Actinomycetes strains were isolated from sediments using Starch Casein Agar medium modified. The antimicrobial activity of these strains was studied using the agar cylinder method, while their ability to degrade crude oil was assessed using the hole-plate diffusion method. Physicochemical properties of sediment samples indicated that the SS sample was a clayey, neutral, slightly salty sediment and had a high level of organic matter. Whereas, the SM and SE samples were no clayey, alkaline sediments with moderate (SM) and low (SE) levels of organic matter. All sediment samples have a low total nitrogen content. 16 strains of actinomycetes were obtained from the SS samples. Antimicrobial activity was assessed against three Gram-positive bacteria, three Gram-negative bacteria, one yeast, and two filamentous fungi. Among the studied isolates, six strains showed activity against at least one of the tested strains. Enrichment culture using a basal mineral salt medium and hole-plate diffusion method revealed that out of 16 cultures, 09 had crude oil biodegradation ability when crude oil was used as a sole carbon source. SSB2 isolate characterization was carried out using morphological, physiological, biochemical, and chemotaxonomic identification methods. These results indicated that the isolated bacterial strain was from Actinomycetales order and the genus Streptomyces. Actinomycetes are of significant interest in both medical and environmental.