Department of Botany and Microbiology, University of Oklahoma, Norman, OK 73019, USA.
J Ind Microbiol Biotechnol. 2011 Apr;38(4):513-21. doi: 10.1007/s10295-010-0794-6. Epub 2010 Aug 10.
The effect of trace metal ions (Co²+, Cu²+, Fe²+, Mn²+, Mo⁶+, Ni²+, Zn²+, SeO₄⁻ and WO₄⁻) on growth and ethanol production by an ethanologenic acetogen, Clostridium ragsdalei was investigated in CO:CO₂-grown cells. A standard acetogen medium (ATCC medium no. 1754) was manipulated by varying the concentrations of trace metals in the media. Increasing the individual concentrations of Ni²+, Zn²+, SeO₄⁻ and WO₄⁻ from 0.84, 6.96, 1.06, and 0.68 μM in the standard trace metals solution to 8.4, 34.8, 5.3, and 6.8 μM, respectively, increased ethanol production from 35.73 mM under standard metals concentration to 176.5, 187.8, 54.4, and 72.3 mM, respectively. Nickel was necessary for growth of C. ragsdalei. Growth rate (μ) of C. ragsdalei improved from 0.34 to 0.49 (day⁻¹), and carbon monoxide dehydrogenase (CODH) and hydrogenase (H₂ase)-specific activities improved from 38.45 and 0.35 to 48.5 and 1.66 U/mg protein, respectively, at optimum concentration of Ni²+. At optimum concentrations of WO₄⁻ and SeO₄⁻, formate dehydrogenase (FDH) activity improved from 32.3 to 42.6 and 45.4 U/mg protein, respectively. Ethanol production and the activity of FDH reduced from 35 mM and 32.3 U/mg protein to 1.14 mM and 8.79 U/mg protein, respectively, upon elimination of WO₄⁻ from the medium. Although increased concentration of Zn²+ enhanced growth and ethanol production, the activities of CODH, FDH, H₂ase and alcohol dehydrogenase (ADH) were not affected by varying the Zn²+ concentration. Omitting Fe²+ from the medium decreased ethanol production from 35.7 to 6.30 mM and decreased activities of CODH, FDH, H₂ase and ADH from 38.5, 32.3, 0.35, and 0.68 U/mg protein to 9.07, 7.01, 0.10, and 0.24 U/mg protein, respectively. Ethanol production improved from 35 to 54 mM when Cu²+ was removed from the medium. The optimization of trace metals concentration in the fermentation medium improved enzyme activities (CODH, FDH, and H₂ase), growth and ethanol production by C. ragsdalei.
研究了痕量金属离子（Co²+、Cu²+、Fe²+、Mn²+、Mo⁶+、Ni²+、Zn²+、SeO₄⁻和 WO₄⁻）对产乙醇厌氧梭菌 Clostridium ragsdalei 在 CO:CO₂ 生长细胞中的生长和乙醇生产的影响。通过改变培养基中痕量金属的浓度来操纵标准产乙醇厌氧梭菌培养基（ATCC 培养基编号 1754）。将标准痕量金属溶液中 Ni²+、Zn²+、SeO₄⁻和 WO₄⁻的单个浓度分别从 0.84、6.96、1.06 和 0.68 μM 增加到 8.4、34.8、5.3 和 6.8 μM，使乙醇产量从标准金属浓度下的 35.73 mM 分别增加到 176.5、187.8、54.4 和 72.3 mM。镍是 C. ragsdalei 生长所必需的。C. ragsdalei 的生长速率（μ）从 0.34 提高到 0.49（天⁻¹），一氧化碳脱氢酶（CODH）和氢化酶（H₂ase）的比活性从 38.45 和 0.35 提高到 48.5 和 1.66 U/mg 蛋白，分别在 Ni²+的最佳浓度下。在 WO₄⁻和 SeO₄⁻的最佳浓度下，甲酸脱氢酶（FDH）的活性分别从 32.3 提高到 42.6 和 45.4 U/mg 蛋白。当从培养基中除去 WO₄⁻时，乙醇产量和 FDH 的活性从 35 mM 和 32.3 U/mg 蛋白分别降低到 1.14 mM 和 8.79 U/mg 蛋白。尽管增加 Zn²+的浓度可以提高生长和乙醇产量，但 CODH、FDH、H₂ase 和醇脱氢酶（ADH）的活性不受 Zn²+浓度变化的影响。从培养基中除去 Fe²+会使乙醇产量从 35.7 降低到 6.30 mM，并使 CODH、FDH、H₂ase 和 ADH 的活性从 38.5、32.3、0.35 和 0.68 U/mg 蛋白分别降低到 9.07、7.01、0.10 和 0.24 U/mg 蛋白。当从培养基中除去 Cu²+时，乙醇产量从 35 提高到 54 mM。发酵培养基中痕量金属浓度的优化提高了 C. ragsdalei 的酶活性（CODH、FDH 和 H₂ase）、生长和乙醇生产。
