Khaliq Shazia, Akhtar Kalsoom, Afzal Ghauri Muhammad, Iqbal Ruqia, Mukhtar Khalid Ahmad, Muddassar Muhammad
Bioprocess Technology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), P.O. Box 577, Jhang Road, Faisalabad, Pakistan.
Microbiol Res. 2009;164(4):469-77. doi: 10.1016/j.micres.2007.02.005. Epub 2007 May 2.
Tylosin is a macrolide antibiotic used as veterinary drug and growth promoter. Attempts were made for hyper production of tylosin by a strain of Streptomyces fradiae NRRL-2702 through irradiation mutagenesis. Ultraviolet (UV) irradiation of wild-type strain caused development of six morphologically altered colony types on agar plates. After screening using Bacillus subtilis bioassay only morphological mutants indicated the production of tylosin. An increase of 2.7+/-0.22-fold in tylosin production (1500mg/l) in case of mutant UV-2 in complex medium was achieved as compared to wild-type strain (550mg/l). Gamma irradiation of mutant UV-2 using (60)Co gave one morphologically altered colony type gamma-1, which gave 2500mg/l tylosin yield in complex medium. Chemically defined media promoted tylosin production upto 3800mg/l. Maximum value of q(p) (3.34mg/gh) was observed by mutant gamma-1 as compared to wild strain (0.81mg/gh). Moreover, UV irradiation associated changes were unstable with loss of tylosin activity whereas mutant gamma-1 displayed high stability on subsequent culturing.
泰乐菌素是一种用作兽药和生长促进剂的大环内酯类抗生素。人们试图通过辐射诱变，利用弗氏链霉菌NRRL - 2702菌株超量生产泰乐菌素。对野生型菌株进行紫外线（UV）照射后，在琼脂平板上出现了六种形态改变的菌落类型。使用枯草芽孢杆菌生物测定法进行筛选后，只有形态突变体显示出泰乐菌素的产生。与野生型菌株（550mg/l）相比，复合培养基中突变体UV - 2的泰乐菌素产量（1500mg/l）提高了2.7±0.22倍。使用（60）Co对突变体UV - 2进行γ辐射，得到一种形态改变的菌落类型γ - 1，其在复合培养基中的泰乐菌素产量为2500mg/l。化学成分明确的培养基可使泰乐菌素产量提高到3800mg/l。与野生菌株（0.81mg/gh）相比，突变体γ - 1观察到的最大q(p)值为（3.34mg/gh）。此外，紫外线照射相关的变化不稳定，泰乐菌素活性丧失，而突变体γ - 1在后续培养中表现出高稳定性。
