Breeding Of Single Component Producer Of Tobramycin And Studies On Its Characters

By treating original s, tenebrarius UVS-51 producing only carbamoyl tobramycin with UV and NTG as mutagens and the tolerant treatment was used, two stable mutants were isolated through the cyclic screening and mixed cultures assay method. The titers of antibiotic produced by the two mutants NS-81 and NT-26 in shaken flasks were 53% and 77% higher than that of the control respectively. They were all identified to be a single component producer of tobramycin by means of TLC.Studies were carried out on genetic stability, fermentation process and cultural characters of the three strains in this paper. Optimum time that the mutants were grown on slant medium were 10d, mature spores were placed in refrigerator for about a week, 10% of inoculum size and 40ml medium in 250ml flask were proved to be the best fermentation condition. At the same time, metabolic changes were observed too.Because the idea of cyclic mutation and the method of mixed cultures assay were introduced in this test, the cycle of the test was shortened widely and the efficiency of mutation breeding was improved effectively. The good mutants could be obtained in a short time.