Abstract

Actinomycetes have been demonstrated for plant growth-promotion, antagonistic against plant pathogens and insect pests and biofortification traits in many agriculturally important crops. The present investigation was conducted to characterize probiotic properties of actinomycete(s) isolated from pearl millet flour and batter samples. A media selective and specific were used for isolation, actinomycetes isolation agar (AIA), and the most prominent actinomycete (found abundantly in the AIA plate) was isolated and maintained on AIA slants at 4°C for further investigation. The most prominent actinomycete was characterized for traits including Gram staining, morphology (such as color, margin, size, shape, elevation, form and surface), biochemistry (such as urease, catalase, oxidase, hydrogen sulphide, nitrogen reduction, gelatin liquefaction, starch hydrolysis and carbohydrate utilization), IMViC tests (such as indole, methyl red, Voges Proskauer and citrate utilization), probiotic potentials (such as acid [pH 2, 3], bile [0.5%], NaCl [6 and 9%], phenol tolerance [0.4%]), antibiotic tolerance (such as tetracycline, streptomycin, kanamycin, chloramphenicol, ciprofloxacin, ampicillin, penicillin, erythromycin and vancomycin) and antimicrobial activities against human pathogens (such as Escherichia coli, Staphylococcus aureus and Salmonella typhi). It was possible to isolate only one probiotic actinomycete based on the properties. The sequences of 16s rDNA gene of the actinomycete was matched with Streptomyces species in BLAST analysis. The sequences of the Streptomyces spp. were submitted to NCBI and accession number obtained. This study indicated that the selected Streptomyces spp. could be used to develop new probiotic foods.

Key words: Probiotics, pearl millet, Streptomyces species, product development.