title: Enhancement of geldanamycin production by pH shock in batch culture of Streptomyces hygroscopicus subsp. duamyceticus.
abstract: Various sequences of pH change were applied in a batch bioreactor to investigate pH shock effects on geldanamycin production by Streptomyces hygroscopicus subsp. duamyceticus JCM4427. In the control culture where the pH was not controlled, the maximum geldanamycin concentration was 414 mg/l. With the pHS1 mode of pH shock, that is, an abrupt pH change from pH 6.5 to pH 5.0 and then being maintained at around pH 5.0 afterward, 768mg/l of geldanamycin was produced. With pHS2, in which the pH was changed sequentially from pH 6.7 to pH 5.0 and then back to pH 6.0, 429 mg/l of geldanamycin was produced. With pHS3 having a sequential pH change from pH 6.0 to pH 4.0 and then back to pH 6.5 followed by the third pH shock to pH 5.5, no geldanamycin production was observed. Considering that the productivity with pHS1 was about two-fold of that of the control culture with no pH control, we concluded that a more sophisticated manipulation of pH would further promote geldanamycin production.
authors.affiliation: Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea.
authors.forename: Jae Yang
authors.initials: JY
authors.lastname: Song
authors.forename: Yoon Jung
authors.initials: YJ
authors.lastname: Kim
authors.forename: Young-Soo
authors.initials: YS
authors.lastname: Hong
authors.forename: Yong Keun
authors.initials: YK
authors.lastname: Chang
mesh_terms: D016227:Benzoquinones / Q000378:metabolism*; D018533:Biomass; D019149:Bioreactors; D006863:Hydrogen-Ion Concentration; D007218:Industrial Microbiology; D047029:Lactams, Macrocyclic / Q000378:metabolism*; D008828:Microbiological Techniques / Q000379:methods*; D013302:Streptomyces / Q000378:metabolism*; D013997:Time Factors
chemical_list: D016227:Benzoquinones; D047029:Lactams, Macrocyclic; C001277:geldanamycin