金属离子对产琥珀酸放线杆菌NJ113厌氧发酵代谢的影响

Effect of metal ions on fermentation and metabolization of Actinobacillus Succinogenes NJ113

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%。

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.