| 摘要 |
PURPOSE:To efficiently produce L-phenylalanine without using an expensive precursor, by aerobically cultivating a specific microorganism belonging to the genus Citrobacter in a liquid culture medium. CONSTITUTION:Citrobacter.freundii IFO13545 is subjected to treatment with N-methyl-N'-nitro-N-nitrosoguanidine to provide a variant strain OFPR72 (FERM-P 9537) having tolerance to a phenylalanine antimetabolite. The resultant variant strain OFPR is then cultivated in a liquid culture medium containing a carbon source, nitrogen source, inorganic salt, etc., at pH 5-9 and 24-37 deg.C for 48-120hr by shaking or aeration. Microbial cells are then separated and removed from the resultant culture fluid to afford the aimed L-phenylalanine by a method for concentration and crystallization or using an ion exchange resin, etc. |
