Biotechnology Bulletin ›› 2015, Vol. 31 ›› Issue (9): 209-217.doi: 10.13560/j.cnki.biotech.bull.1985.2015.09.030

• Research report • Previous Articles     Next Articles

Influence of Perturbation of Energy Metabolism in Escherichia coli K235 on Biosynthesis of Polysialic Acid

Yan Xia, Wu Jianrong, Zheng Zhiyong, Zhan Xiaobei   

  1. (Key Laboratory of Carbohydrate Chemistry & Biotechnology of Ministry of Education,School of Biotechnology,Jiangnan University,Wuxi 214122)
  • Received:2014-12-19 Online:2015-09-15 Published:2015-09-16

Abstract: Different medium volumes, carbon sources with varied redox states and adding nicotinic acid, and the precursor of NAD+ were used to adjust the intracellular energy charge and reduction of Escherichia coli in order to investigate the relationships between biosynthesis of polysialic acid and intracellular nucleotides. The results showed that the higher the production of polysialic acid was, the lower UTP was, but higher UMP was. Meanwhile, energy charge level was lower because the synthesis of UTP and CTP consumed a lot of ATP. Using sorbitol as carbon source, more polysialic acid was produced than those of fermentation with glucose, xylose and sodium gluconate due to the increase of NADH. Addition of nicotinic acid to the fermentation medium elevated intracellular NAD+, which led to the raise of intracellular oxidative stress, sequentially the decrease of the reducing metabolites such as polysialic acid, succinate and lactate, and even the vanish of them.

Key words: Escherichia coli, polysialic acid, energy charge, nucleotides, redox potential