الفهرس Only 14 pages are availabe for public view
 |  | from | 178 |  |  |
| | | from | 178 | | |
Abstract
The main objective of the present study is to improve clavulanic acid (CA) production using UV-mutagenesis on Streptomyces sp. NRC 77. from the screened mutants, 120A3 mutant isolate was selected as a promising one .The biochemical, morphological, physiological properties of 120A3 mutant showed culture characteristics similar to Streptomyces sp. Phylogenetic analysis of the 16S rDNA gene sequence showed that this strain has a similarity of (99 %) to Streptomyces sp. T2-7, therefore it was suggested as Streptomyces sp. MU-NRC 77 and its nucleotide sequence was deposited in Gen Bank under the accession No. KT953342. Improvement of CA yield by 572.49 mg/l was obtained from fermentation medium and culture condition optimization in compared with 130.69 mg/l for wild strain. Further optimized by the addition of H2O2 and activated plant charcoal (1%) to the production medium increased CA yield strongly to reach 646.12 and 682.94 mg/l respectively by production incresement 5.2 fold more than that obtained before adding. Production of CA by the new selected Streptomyces mutated isolate using bioreactor 7L under optimized medium and conditions (agitation speed effect) afforded the highest CA yield 719.75 mg/l at 600 rpm by production incresement 5.5 fold in comparison with the wild strain, then extraction, purification of the CA from fermentation broth and chemical elucidation was carried out using different spectroscopic analysis