Optimization of Ectoine Synthesis through Fed-Batch Fermentation of Brevibacterium epidermis
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- 作者：Annelies E. Onraedt ; Bart A. Walcarius ; Wim K. Soetaert ; and Erick J. Vandamme
- 刊名：Biotechnology Progress
- 出版年：2005
- 出版时间：August 2005
- 年：2005
- 卷：21
- 期：4
- 页码：1206 - 1212
- 全文大小：132K
- 年卷期：v.21,no.4(August 2005)
- ISSN：1520-6033
文摘
A production process for ectoine has been developed, using Brevibacterium epidermisDSM20659 as the producer strain. First, the optimal conditions for intracellularsynthesis of ectoine were determined. The size of the intracellular ectoine pool is shownto be dependent on the external salt concentration, type of carbon source, and yeastextract concentration. Under the optimized conditions of 1 M NaCl, 50 g/L monosodiumglutamate, and 2.5 g/L yeast extract, a maximum concentration of intracellular ectoineof 0.9 g/L was obtained in shake flask cultures. After optimizing the batch fermentationparameters of temperature, pH, agitation, and aeration, the yield could be furtherincreased by applying the fed-batch fermentation principle in 1.5- to 2-L fermentors.Glutamate and yeast extract were fed to the bacterial cells such that the totalglutamate concentration in the broth remained constant. A total yield of 8 g ectoine/Lfermentation broth was obtained with a productivity of 2 g ectoine/L/day. After thebacterial cells were harvested from the culture broth, the ectoine was recovered fromthem by a two-step extraction with water and ethanol. Crystallization of the productwas obtained after concentration of the extract via evaporation under reduced pressure.After this downstream process, 55% of the ectoine produced in the fermentor could becrystallized in four fractions. The first fractions were of very high purity (98%). Thisproduction process can compete with other described production processes for ectoinein productivity and simplicity. Further advantages are the relatively low amounts ofNaCl needed and the absence of hydroxyectoine, often a byproduct, in the final product.