Effect of adding intermediate metabolites on succinate production by Actinobacillus succinogenes / 生物工程学报

We investigated the effect of adding intermediate metabolites on cell growth and succinate production. The yield of succinic acid achieved to the highest when 0.5 g/L phosphoenolpyruvic acid (PEP) was added. According to the metabolic network of Actinobaccilus succinogenes NJ113, the metabolic flux was calculated by metabolic flux analysis. The ratio of hexose monophosphate pathway to glycolytic pathway increased from 39.4:60.3 to 76.8:22.6 after adding 0.5 g/L PEP, thus the reducing power was better balanced. The flux of PEP to oxaloacetate was 23.8% higher, which made the succinic acid flux improve from 99.8 mmol/(g DCW x h) to 124.4 mmol/(g DCW x h) and the flux of acetic acid and formic acid decreased by 22.9% and 15.4%, respectively. The key enzyme activity analysis showed that the specific activity of PEP carboxykinase reached to 1910 U/mg with 0.5 g/L PEP addition, which was 74.7% higher than the control; and the specific activity of pyruvate kinase decreased by 67.5%. Finally, the concentration of succinic acid was 29.1 g/L with the yield of 76.2%.

Effects of different neutralizing agents on succinate production by Actinobacillus succinogenes NJ113 / 生物工程学报

Different neutralizing agents were used as pH controller to investigate their effects on the growth and succinic acid production of Actinobacillus succinogenes NJ113. The fermentation results showed that Ca(OH)2, CaCO3 and NH4OH were not suitable for succinic acid production by A. succinogenes NJ113 because of their negative effects on cell growth. When Na-base was used, cells would flocculate and lump, and due to the sodium ion concentration reaching to a high level, OD660 dropped sharply after 12 h of fermentation. Mg-base was better because there was no significant inhibition by magnesium ion. Two combined neutralizing agents were used to maintain pH level, one with NaOH and Mg(OH)2 while the other with Na2CO3 and Mg(OH)2. The optimum ratios of the combined neutralizing agents were both 1:1 (g:g) when using 100 g/L glucose. When NaOH and Mg(OH)2 were chosen with the ratio of 1:1(g:g), 69.8 g/L of the succinic acid and 74.5% of the yield was obtained.

Impact of saiga horn capsule on blood pressure variability,pulse pressure and left ventricular mass in elderly patients with isolated systolic hypertension / 中华中医药杂志

Objective:To observe the efficacy of saiga horn capsule combining with benazapril on blood pressure variability,pulse pressure and left ventricular mass in elderly patients with isolated systolic hypertension (ISH).Methods:78 elderly patients with ISH were treated with saiga horn capsule combining with benazapril for 4 months.We compared the change of 24hours systolic blood pressure (SBP),24hours diastolic blood pressure (DBP),pulse pressure (PP) and left ventricular mass.Results:After four months treatment,reduction of 24 hour SBP variability,day SBP variability,DBP variability,night SBP variability day,24 hour and day average BP variability,pulse pressure and left ventricular mass had statistical signifi cance (P0.05).Conclusion:The elderly patients with ISH treated with saiga horn capsule and benazapril can lower blood pressure,pulse pressure more effective,therefore protect target organ better than with benazapril only.