title: Medium composition suitable for L-lysine production by Methylophilus methylotrophus in fed-batch cultivation.
abstract: L-Lysine production was investigated in fed-batch fermentation using L-lysine producer of Methylophilus methylotrophus. By the addition of nutrient composition, containing L-methionine, K(2)HPO(4), NaH(2)PO(4), CuSO(4).5aq, MnSO(4).5aq, ZnSO(4).7aq, FeCl(3), MgSO(4).7aq and CaCl(2).2aq, in the feed medium, cell growth could be maintained through the cultivation, and L-lysine production reached to 7.86 g. In addition, the effect of counter ion for NH(4)(+) (Cl(-), SO(4)(2-), glutamate, succinate and citrate) was examined. The result showed that the cell growth in the medium using Cl(-) and glutamate were improved compared with that using SO(4)(2-), succinate and citrate, and L-lysine production in the medium using Cl(-) and glutamate reached to more than 9.0 g. In this experiment, there was a clear correlation between ionic strength and growth rate in the cultivation. In order to examine the influence of ionic strength on growth rate, the activity of enzymes in central metabolic pathway from methanol to pyruvate were assayed using samples at the log-phase and the stationary phase in fed-batch cultivation using (NH(4))(2)SO(4) and (NH(4))Cl as ammonium source. It was found that the higher ionic strength inhibited methanol oxidation activity, which linked to cell growth. In this report, it was revealed that maintaining a relatively low ionic strength had a positive effect on L-lysine production using L-lysine producer of M. methylotrophus.
authors.affiliation: Fermentation and Biotechnology Laboratories, Ajinomoto Co., Inc., 1-1 Suzuki-cho, Kawasaki-ku, Kawasaki 210-8681, Japan. kouhei_ishikawa@ajinomoto.com
authors.forename: Kohei
authors.initials: K
authors.lastname: Ishikawa
authors.forename: Yuriko
authors.initials: Y
authors.lastname: Toda-Murakoshi
authors.forename: Fumito
authors.initials: F
authors.lastname: Ohnishi
authors.forename: Kazuya
authors.initials: K
authors.lastname: Kondo
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Osumi
authors.forename: Kozo
authors.initials: K
authors.lastname: Asano
mesh_terms: D003470:Culture Media; D005285:Fermentation; D008239:Lysine / Q000096:biosynthesis*; D020630:Methylophilus methylotrophus / Q000378:metabolism*; D009994:Osmolar Concentration; D000644:Quaternary Ammonium Compounds / Q000378:metabolism
chemical_list: D003470:Culture Media; D000644:Quaternary Ammonium Compounds; D008239:Lysine