Characterization and production improvement of cytotoxic agent(s) produced by Streptomyces parvus isolate S86 and Streptomyces griseus isolate S131

Abstract

Two Streptomyces isolates namely S. griseus coded S131 (NCBI accession code KJ623766) and S. parvus coded S86 (NCBI accession code KJ623765), showed significant cytotoxic activities against various cancer cell lines, were recovered from Egyptian soil samples in our previous studies. The present study was started with the production of the cytotoxic agents by the respective isolates at large scale level using laboratory fermenter, followed by purification and structural elucidation of the biological active molecular entities. In addition, the gene(s) involved in the biosynthesis of the identified cytotoxic metabolites have been identified. Finally production improvement has been carried out by mutation using gamma radiation. The production of cytotoxic metabolites from S. griseus, KJ623766 and S. parvus KJ623765 in 14 L laboratory fermenter was carried out under specified optimum conditions (28°C temperature, 200 rpm rotation speed, uncontrolled pH, 3 vvm aeration and 2 bar airflow pressure). After 72 h of incubation, about 1 L of CFCS of each isolate was extracted with ethyl acetate at the level of 1:1 (v/v) in subsequent