Abstract:

The effects of adding Mg²⁺，Mn²⁺，Co²⁺ on cell growth and succinic acid production was investigated. The metabolic flux of Actinobacillus succinogenes NJ113 was calculated. It was found that the flux of HMP increased by 445.38%，176.23 % and 171.67% after adding 6 mmol/L Mg²⁺，6 mmol/L Mn²⁺， 2 mmol/L Co²⁺ respectively，thus the reducing power was better balanced. The flux of C₄ was 57.70%，15.94% and 2.91% higher respectively，which led to the improvement of succinic acid flux by 62.69%，18.91% and 5.01%. The key enzyme activity analysis showed that the specific activity of PEP carboxykinase（Pck）reached 568.732 U/mg，728.049 U/mg and 339.686 U/mg with 6 mmol/L Mg²⁺，6 mmol/L Mn²⁺，2 mmol/L Co²⁺ addition respectively. As a result，the concentration of succinc acid was 27.83 g/L，26.27 g/L，and 23.54 g/L，while the concentration of control was only 22.79 g/L.

摘要：

考察了培养基中分别添加Mg²⁺、Mn²⁺、Co²⁺ 3种金属离子对Actinobacillus succinogenes NJ113菌体生长及产酸的影响，并进行了代谢通量分析。结果表明培养基中分别添加6 mmol/L Mg²⁺、6 mmol/L Mn²⁺、2 mmol/L Co²⁺后流向HMP途径的通量r₁₇比对照组分别提高了445.38%、176.23 %和171.67%，使得还原力不足的矛盾得到缓解；流向C₄途径的通量r₁₃比对照组分别提高了57.70%、15.94%和2.91%；最终使得流向丁二酸的通量r₁₆比对照组分别提高了62.69%、18.91%和5.01%。此外，关键酶活分析结果显示分别添加Mg²⁺、Mn²⁺以及Co²⁺后，PEP羧化激酶（Pck）比活力由对照组的339.18 U/mg分别提高到568.732 U/mg、728.049 U/mg和339.686 U/mg。最终当培养基中分别添加6 mmol/L Mg²⁺、6 mmol/L Mn²⁺、2 mmol/L Co²⁺后丁二酸产量分别为27.83 g/L、26.27 g/L和23.54 g/L，比对照的22.79 g/L分别提高22.11%、15.27%以及3.4%。