Bioactivity of Marine Streptomyces sp. VITJS4: Interactions of Cytotoxic Phthalate Derivatives with Human Topoisomerase II α: An In Silico Molecular Docking Analysis.

Despite clinical advances in antimicrobial and anticancer therapy, there is an urge for the search of new bioactive compounds. In the present study, previously isolated Streptomyces sp. VITJS4 strain (NCIM No. 5574) (ACC No: JQ234978.1) crude extract tested for antibacterial activity showed a broad spectrum at the concentration of 20 mg/mL against pathogens. The antioxidant potential tested at 0.5 mg/mL concentration exhibited reducing power activity with a maximum of 90 % inhibition. The anticancer property by MTT assay on HeLa and HepG2 cells showed cytotoxic effect with IC50 of 50 µg/mL each. The DNA fragmentation pattern observed in both HeLa and HepG2 cell indicated laddering pattern at 40 µg/mL concentration. GC-MS analysis revealed that the significant peak corresponding at m/z 149 (M+) was identified as phthalate derivatives. The extract was further separated by HPLC with their retention times (t r) at 6.294 min. The above-obtained results were also supported by molecular docking studies which provide an insight into ligand binding to the active site of the receptor. The in silico docking studies revealed better binding affinity with a binding energy of -5.87 kJ mol-1 of the ligand toward topoisomerase II α.

Strain improvement and optimization studies for enhanced production of erythromycin in bagasse based medium using Saccharopolyspora erythraea MTCC 1103.

In the present study, Saccharopolyspora erythraea MTCC 1103 was used for the enhanced production of erythromycin. To enhance the yield of erythromycin, effects of various parameters such as bagasse concentration, organic nitrogen source, inorganic nitrogen source, pH and temperature were analysed. It was found that bagasse can be used as an alternate carbon source in erythromycin production medium. Erythromycin production in the new formulation of bagasse based medium was found to be 512 mg/L which was 28 % higher than glucose based medium. Strain improvement was done by random UV-mutagenesis. When compared to wild type strain, mutant strain showed 40 % higher yield in production medium. Erythromycin potency assay and HPLC analysis were performed to confirm the presence of erythromycin in the partially purified samples. These optimized conditions could be used for the commercial production of this unique antibiotic which gave significant industrial perspectives.

Studies on growth kinetics of Serratia marcescens VITSD2 and optimization of fermentation conditions for serratiopeptidase production.

Serratia is one of the most important groups of bacteria which produces proteolytic enzymes effectively and known to possess anti- inflammatory properties. The main focus of the current study was to optimize the culture conditions of Serratia marcescens VITSD2 for the mass production of serratiopeptidase. Effect of various nutritional and environmental factors were analysed and optimized. Among the different carbon and nitrogen sources tested, mannose and soya bean meal was found to be the best with enzyme activity of 1391 units /mL and 1800 U/mL respectively. The enzyme showed an optimum activity of 1668 U/mL at pH-8 and 1500 U/mL at 25ºC. Maximum peptidase production during fermentation was obtained after 24 h incubation with 1% inoculum in the medium at 25ºC and yielded 1668 U/mL. Lysine stimulated the production of peptidase and the yield obtained was 2410U/mL. Growth curve analysis was done. Maximum serratiopeptidase production was detected after 24 h incubation with 2155 units/mL and cell density of 2.4g/100mL. Hence the observation of the present study clearly indicates that the yield of Serratiopeptidase was found to be maximum by varying the cultural conditions.