Microbiological and molecular characterization of thermophilic Streptomycesvariabilis with antimicrobial activity

Document Type : Original Article

Authors

Botany Department, Faculty of Science, Benha University, Benha, Egypt

Abstract

The rise of antibiotic resistance phenomena increased the interest for finding effective antimicrobial alternatives to control 
microbial pathogens. Actinomycetes represent a great reservoir for isolation and identification of antimicrobial compounds. 
In this study, various samples were randomly collected from the soil of different places in south Delta in Egypt. Two isolates 
of thermophilic Streptomyces spp were isolated on starch nitrate agar under thermophilic conditions, and were identified 
according to their morphological characteristics. Only, one isolate showed antifungal and antibacterial activity against 
various fungal and bacterial pathogens including Staphylococcus aureus, Escherichia coli and Streptococcus. Maximum 
antimicrobial activity was detected against Aspergillus niger. This isolate was identified as Streptomyces variabilisEG1on the 
base of the morphological characteristics and 16s rRNA gene sequencing. Optimization of some culture conditions was 
studied for attaining maximum antimicrobial agent production. This was achieved via adjusting carbon, nitrogen sources 
including starch and potassium nitrate, pH, time and temperature. Antimicrobial agent production by S.variabilis EG1 was 
observed on the 5th day of growth on the starch nitrate culture media (incubation at 50° C and pH 7.0) and was efficiently 
extracted by many solvents. This work confirmed the ability of thermophilic actinomycetes, S. variabilisEG1 to produce 
unpurified antimicrobial agents for pharmaceutical applications.

Keywords

Journal of Basic and Environmental Sciences
Volume 5, Issue 1
January 2018
Pages 34-43

Files

Share

How to cite

Statistics