Screening and Characterization of Bacteria That Can Utilize Ammonium and Nitrate Ions Simultaneously under Controlled Cultural Conditions(ENVIRONMENTAL BIOTECHNOLOGY)

概要

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Eighteen bacterial stock cultures were examined for their ability to utilize NH_4^+ and NO_3^- simultaneously in a medium containing NH4_NO_3 with shaking using a test tube capped with a cotton stopper. Pseudomonas aeruginosa NBRC 12689 utilized 1 mg/ml of NH_4NO_3 most rapidly of the cultures tested. The bacterium could completely utilize 5 mg/ml of NH_4NO_3 within 3d, 6mg/ml of NH_4Cl within 3 d, and 20 mg/ml of NaNO_3 within 2d under optimum conditions. The addition of Fe^<2+> to the NH_4NO_3 medium markedly promoted the utilization of the two ions. When the Pseudomonas strain utilized 5mg/ml of NH_4NO_3 completely, the total nitrogen in the culture including its cells decreased to 41% of that of the NH_4NO_3 originally provided. GC-MS analysis showed that the removed nitrogen was probably denitrified. When the bacterium was incubated in the NH_4NO_3 medium with shaking in a vial sealed with a rubber stopper, N_2 accumulated, but not N_2O at the final phase of cultivation. On the other hand, both N_2 and N_2O were detected in the NaNO_3 medium. We concluded that the bacterium removed NH_4^+ from NH_4NO_3 as a nitrogen source for its cell components, together with the denitrification of NO_3^- under controlled shaking conditions. In addition, NH_4^+ promoted the cell growth of the bacterium and denitrification to N_2, preventing the accumulation of N_2O.
社団法人日本生物工学会の論文
2007-02-25