Escherichia coli engineering bacteria for producing L-serine with high yield and fermentation method for engineering bacteria

Abstract

The invention relates to escherichia coli engineering bacteria for producing L-serine with high yield and a fermentation method for the engineering bacteria. The bacteria are escherichia coli Q3 with the collection number CGMCC 6213, and the genotype of the bacteria is MG1655 delta sdaA delta sdaB delta tdcG:: Cm. By using wild escherichia coli as a contrast, the culture results show that in a fermentation medium (containing 10 g / L of peptone, 5 g / L of yeast powder, 10 g / L of sodium chloride and 10 g / L of glucose), under the fermentation culture conditions that the pH value is 7.0, the temperature is 37+ / -1 DEG C, the revolving speed of a shaker is 200+ / -20 revolutions per minute and the fermentation time is 48+ / -3 hours, the accumulation quantity of the L-serine produced by fermenting the engineering bacteria is improved by about 40 percent, a foundation is laid for constructing high-yield strains of phosphatidylserine, and the engineering bacteria have important application prospect and value.

Description

technical field [0001] The invention belongs to the field of genetic engineering and microbial fermentation, and relates to a high-yield L-serine Escherichia coli engineering bacterium and a fermentation method thereof. technical background [0002] L-serine is a non-essential amino acid that has many important physiological functions and is widely used in medicine, food and other fields. At present, the methods for synthesizing L-serine mainly include biological methods such as chemical synthesis, silk hydrolysis, enzymatic method, and precursor fermentation method, among which the product produced by chemical synthesis is a mixture of D-serine and L-serine; silk hydrolysis The operation is complicated, and a large amount of eluent needs to be processed, and the obtained amino acids are mixed amino acids; the requirements for immobilized enzymes are relatively high during enzymatic synthesis, and the separation of L-serine from the enzymatic reaction solution has always bee...

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Problems solved by technology

[0004] Elaine Newman et al. (2008, MolecμLar Microbiology.69(4), 870–881) described the effects of simultaneous deletion of three genes sdaA, sdaB, and tdcG on the growth and division of Escherichia coli MEW999 strain, but did not measure the effect of L - The accumulation of serine, and the fermentation conditions have not been optimized

However, domestic patents on the construction of engineering strains that simultaneously delete the three genes sdaA, sdaB and tdcG on the basis of E. coli metabolic pathways and their regulation methods have not yet been reported.

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