title: Effects of dissolved oxygen level on rapamycin production by pellet-form of Streptomyces hygroscopicus.
abstract: Rapamycin was known to have the functions of being an antibiotic and immunosuppressant; recently it was also recognized as being able to retard the aging process. The effects of dissolved oxygen (DO) level on rapamycin production by pellet-form of Streptomyces hygroscopicus were investigated in this study. The results suggest that a high DO level is required to enhance rapamycin production. However, the premise for getting a high rapamycin concentration by using DO control was keeping the intact of pellet-form of S. hygroscopicus. What if the high DO level achieved was coming from the increase of agitation; it might break down the morphology of pellets-form in the fermentation tank and result in the decrease of rapamycin production. The maximum rapamycin obtained in this study was about 780 mg/L in the 5 L fermentor batch with DO controlled over 30%, with the supplement of pure oxygen in the inlet gas, and the agitation speed limited to less than 200 rpm. Conclusively, a high DO level and the morphology of pellets form both were detrimental to achieving a high rapamycin production by S. hygroscopicus in the agitation fermentor.
authors.affiliation: Department of Chemical and Materials Engineering, Tunghai University, 181, Taichung Harbor Rd, Taichung 407, Taiwan, ROC. hwyen@thu.edu.tw
authors.forename: Hong-Wei
authors.initials: HW
authors.lastname: Yen
authors.forename: Hsin-Pei
authors.initials: HP
authors.lastname: Hsiao
mesh_terms: D000900:Anti-Bacterial Agents / Q000096:biosynthesis*; D019149:Bioreactors; D005285:Fermentation / Q000187:drug effects; D010100:Oxygen / Q000378:metabolism* / Q000494:pharmacology*; D020123:Sirolimus / Q000378:metabolism*; D013302:Streptomyces / Q000187:drug effects* / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D010100:Oxygen; D020123:Sirolimus
keywords: Dissolved oxygen; Morphology; Pellet; Rapamycin; Shear force