Screening for agroactive and bioactive metabolites production by actinobacteria isolated from rhizospheric soils

In this study, agroactive and bioactive compound production by actinobacteria isolated from rhizospheres of different plants was screened. Six of the forty-two isolates showed the highest production of different compounds and were identified by using molecular methods. In the primary and secondary screening antimicrobial activities were determined by inhibition zones against six bacterial and three fungal pathogens. Streptomyces labedae CYP25 showed the highest antibacterial activity in screening with extracts obtained from Actinomycetes Isolation Broth (AIB) against Staphylococcus aureus (18 mm); Streptomyces sp. CYP30 showed the highest antifungal activities in screening with ethyl acetate extracts obtained from Glucose Soybean Meal Broth against Candida albicans (60 mm) and Alternaria sp. D21 (52 mm) and showed the highest antifungal activities in screening with extracts obtained from International Streptomyces Project-3 (ISP-3) Broth against Aspergillus niger (16 mm). The highest indole acetic acid (IAA) production was showed by Nocardiopsis sp. CYP39. This isolate produced the highest amount of IAA (76.5 mu g/mL) in the presence of 0.9% L-tryptophan. Thirty-two of forty-two isolates were identified as siderophore producers. The best hydrogen cyanide producer was Nocardiopsis sp. CYP15. Streptomyces moderatus CYP35 and Streptomyces chartreusis CYP19 constitute the highest halo-zone diameter on phosphate solubilizing activity tests.