ATP Production from Adenine by a Self-coupling Enzymatic Process : High-level Accumulation under Ammonium-limited Conditions
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概要
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To improve ATP production from adenine, we optimized cultivation and reaction conditions for the ATP producing strain, Corynebacterium ammoniagenes KY13510. In the conventional method, 28% NH_4OH has been used both to adjust pH during cultivation and reaction, and to provide nitrogen for cell growth. In the ATP-producing reaction, high concentrations of inorganic phosphate and magnesium ion are needed, which form magnesium ammonium phosphate (MgNH_4PO_4) precipitate. To keep inorganic phosphate and magnesium ions soluble in the reaction mixture, it was indispensable to add phytic acid as a chelating agent of divalent metal ions. Under such conditions, 37 mg/ml (61.2 mM) ATP was accumulated in 13h (Appl. Microbiol. Biotechnol. 21,143 1985). If ammonium ion was depleted from the reaction mixture to avoid MgNH_4 PO_4 formation, we expected that there was no need to add phytic acid and ATP accumulation might be improved. Therefore, we obtained the cultured broth of C. ammoniagenes KY13510 strain with low ammonium ion content (less than 1 mg/ml as NH_3) by the method that a part of alkali solution (28% NH_4OH) for pH control was replaced with 10 N KOH. Using this culture broth, ATP producing reaction was done in 2-liter jar fermentor, controlling the pH of the reaction mixture with 10 N KOH. Under these conditions, the rate of ATP accumulation improved greatly, and 70.6 mg/ml (117 mM) ATP was accumulated in 28 h. The molar conversion ratio from adenine to ATP was about 82%. Phytic acid was slightly inhibitory to ATP formation under these ammonium-limited conditions.
- 社団法人日本農芸化学会の論文
- 2001-03-23
著者
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Maruyama Akihiko
Bio-chemicals Development Department Bio-chemicals Division
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Fujio Tatsuro
Research And Development Division Kyowa Hakko Kogyo Co. Ltd.