Surfactant Supplementation to Enhance the Production of Vitamin K2 Metabolites in Shake Flask Cultures Using Escherichia sp. Mutant FM3-1709
Yan Liu1,2, Zhi-Ming Zheng1*, Hong-Wei Qiu3, Gen-Hai Zhao1, Peng Wang1, Hui Liu1, Li Wang1 , Zhe-Min Li1, He-Fang Wu1, Hong-Xia Liu1 and Mu Tan1
1Key Laboratory of Ion Beam Bioengineering, Chinese Academy of Sciences, Anhui, 230031 Hefei, PR China
2College of Biochemical Engineering, Anhui Polytechnic University, Anhui, 241000 Wuhu, PR China
3National Center for Biotechnology Development, 100036 Beijing, PR China
Article history:
Received March 17, 2013
Accepted January 31, 2014
Key words:
surfactant, vitamin K2, shake flask cultures
Summary:
The effects of the addition of various surfactants on the cell growth and production of vitamin K2 metabolites, such as intracellular menaquinone-4 (MK-4), extracellular MK-4, intracellular MK-6 and extracellular MK-6, were studied in the submerged culture of Escherichia sp. All of the added surfactants caused the extension of the exponential phase. Betaine, polyoxyethylene oleyl ether and Tween-80 were favourable to the cell growth of Escherichia sp. mutant strain FM3-1709. The highest cell growth (Xmax), biomass production rate (Qx) and biomass yield (Yx/s) were (12.6±0.2) g/L, (0.21±0.01) g/(L·h) and (2.42± 0.02) g/g, respectively. The results show that the addition of all surfactants led to a lower production of intracellular MK-4, whereas the production of extracellular MK-4 increased remarkably. Among the five investigated surfactants, the addition of the nonionic surfactant polyoxyethylene oleyl ether (1.0 g/L) led to the highest production of extracellular MK-4 ((33.6±0.4) mg/L), MK-6 ((2.56±0.07) mg/L) and the highest yield of total MK-4 ((47.6±0.4) mg/L) and MK-6 ((6.0±0.1) mg/L). The addition of polyoxyethylene oleyl ether proved to be more beneficial for the secretion of MK-4 than MK-6.
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