Medium composition suitable for L-lysine production by Methylophilus methylotrophus in fed-batch cultivation.
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.
Ishikawa
Kohei
K
Fermentation and Biotechnology Laboratories, Ajinomoto Co., Inc., 1-1 Suzuki-cho, Kawasaki-ku, Kawasaki 210-8681, Japan. kouhei_ishikawa@ajinomoto.com
Toda-Murakoshi
Yuriko
Y
Ohnishi
Fumito
F
Kondo
Kazuya
K
Osumi
Tsuyoshi
T
Asano
Kozo
K
D003470:Culture Media; D005285:Fermentation; D008239:Lysine / Q000096:biosynthesis*; D020630:Methylophilus methylotrophus / Q000378:metabolism*; D009994:Osmolar Concentration; D000644:Quaternary Ammonium Compounds / Q000378:metabolism
D003470:Culture Media; D000644:Quaternary Ammonium Compounds; D008239:Lysine