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The genus Streptomyces, known as prolific antibiotic products and many other bioactive secondary metabolites, is a unique subgroup of actinomycetes bacteria. This study aims to isolate Streptomyces strains from plant rhizosphere that has antibacterial activity. Soil samples were collected from Saudi Arabia. About 39 isolates of Streptomyces sp. were obtained from 12 soil samples, using serial dilution and plating techniques on the solid starch nitrate medium. The Streptomyces strains were cross streaked against some human pathogen bacteria. Against various pathogenic bacteria, only 16 out of 39 isolates demonstrated strong antimicrobial activity. The most active strain Streptomyces NM38 was chosen for secondary screening and identification. The molecular identification was confirmed using 16S rRNA as Streptomyces globosus, the phylogenetic tree was built; the sequence was presented to the GenBank under the accession number: MN538259.1.

Chitin and chitinolytic are beneficial enzymes for their biotechnological applications. Chitinases contribute to the generation of carbon and nitrogen in the ecosystem and can prohibit many fungal ailments that can threaten crop production worldwide. The goal of this work was the production and characterization of chitinase enzymes from bacteria isolated from the western region, Saudi Arabia for biocontrol fungal pathogens. Colloidal chitin from shrimp shells was prepared and used for isolation of chitinolytic bacteria on Mineral chitin agar medium from different sources. The most active isolates were AMM1which was characterized and identified as Alcaligenes aquatilis using 16SrRNA.. In conclusion, purified chitinase was success to produce from Alcaligenes aquatilis for medical uses and biocontrol process.

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The genus Streptomyces is a unique subgroup of actinomycetes bacteria that is well-known as prolific products of many bioactive secondary metabolites as well as antibiotics. Streptomyces globosus (S. globosus) is a bacterium species from the genus of Streptomyces. Objective: This study aimed to optimize the growth conditions required for the maximum antibacterial activity of S. globosus isolated from soil samples in Saudi Arabia. The effect of dark/light, temperature, and pH on the growth and antibacterial effect against E. coli ATCC35218, E. coli ATCC25922, Salmonella sp., P. aeruginosa ATCC27853, S. aureus ATCCBAA977, and St. pneumonia ATCC49619 were optimized. The results of this study showed that. The highest antibacterial activity was at 30 ° C after 7 days of incubation. Furthermore, the best to produce antibacterial activity was under alkaline conditions (pH 8.5). Besides, the isolate didn't show antibacterial activity at the shaking incubator. This study showed that all organic solvents (ethyl-alcohol, methanol, chloroform, ethyl-acetate, and acetone) successfully extracted the antibacterial compound. Still, the compounds extracted by chloroform had the highest antibacterial activity. The MIC of the chloroform extract was against S. aureus ATCCBAA977. The study described the optimized condition for best S. globosus activity. The S. globosus showed a broad spectrum of antimicrobial activities against the test organisms. This opened further research investigations on the purification and structural characterization of the active compounds from the crude extract.