Isolation and Characterization of Actinobacteria from Algerian Saline Soil Samples with Antimicrobial Activities against Microbial Pathogens

Abstract

Unidentified microorganisms that can be employed to make new, bioactive compounds with industrial potential may exist in extreme conditions. Given that actinomycetes are abundant in natural settings, numerous approaches have been developed for isolation, including pretreatments, enrichment, antibiotic combinations, specific isolation media, and some conventional methods. In order to identify untapped producers of novel antimicrobial chemicals, 32 actinomycetes were therefore isolated from 3 soil samples taken from the Saline soil of Sebkha in Oran, Algeria, for this research. All the isolates were further subjected to antimicrobial screening against pathogenic bacteria, and yeast. The obtained results indicated that eight of the isolates (named SO1, SO3, SO4, SO6, SO7, SO9, SO12, and SO14) showed antimicrobial activities against Gram-positive and Gram-negative bacteria, and the majority of the isolates exhibited potent antimicrobial activity. As a result, Streptomyces. sp was recognized as the predominant species in these eight isolates, using morphological, biochemical, and physiological techniques. Isolates of actinomycetes have been subjected to biochemical tests such as starch and casein hydrolysis through the activities of amylase and caseinase. The results of antibiotic sensitivity in a solid medium of the tested isolates reveal that some isolates are susceptible with diameter zones ranging from 16mm to 45mm, while others are resistant or intermediate to the tested antibiotics with diameter zones of 0mm to 15mm. Future research based on the isolation of bioactive metabolites and molecular characterization of isolated Streptomyces sp will help in the identification of new compounds of significant industrial value.