title: Production of soluble human interleukin-6 in cytoplasm by fed-batch culture of recombinant E. coli.
abstract: The major objective of this study is to identify fed-batch culture conditions optimal for the production of human interleukin-6 (hIL-6) in a soluble form. Five different expression vectors were constructed for the expression of hIL-6 and hIL-6s fused with NusA, maltose binding protein (MBP), thioredoxin (Trx) or ubiquitin (Ubi). A series of flask cultures were conducted in LB medium at 37 degrees C. The intact hIL-6 was expressed mostly in the form of inclusion body. More than 95% of the hIL-6 fused with NusA (NusA/hIL-6) and about 90% of MBP/hIL-6 were expressed in a soluble form, whereas Trx/hIL-6 and Ubi/hIL-6 were expressed mostly in the form of inclusion body. Based on this result, NusA was selected as the fusion partner for the production of hIL-6 in the subsequent experiments. A series of pH-stat fed-batch cultures of an E. coli BL21(DE3) transformed with a NusA/hIL-6 expression vector were conducted in a bioreactor with a working volume of about 3 L. As the amount of nitrogen source was increased in the feeding medium, more soluble NusA/hIL-6 was produced, while the total amount was not significantly changed. Under the best conditions tested, about 90% of NusA/hIL-6 was produced in the soluble form. In this case, the concentration of soluble NusA/hIL-6 was 7.5 g/L with a volumetric productivity of 0.43 g/L-h.
authors.affiliation: Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701, Korea.
authors.forename: Tae Wan
authors.initials: TW
authors.lastname: Kim
authors.forename: Bong Hyun
authors.initials: BH
authors.lastname: Chung
authors.forename: Yong Keun
authors.initials: YK
authors.lastname: Chang
mesh_terms: D001483:Base Sequence; D019149:Bioreactors; D017931:DNA Primers; D004926:Escherichia coli / Q000235:genetics*; D006801:Humans; D015850:Interleukin-6 / Q000096:biosynthesis* / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D011995:Recombination, Genetic; D012995:Solubility
chemical_list: D017931:DNA Primers; D015850:Interleukin-6; D011994:Recombinant Proteins