Recombinant Shikimic Acid Strain Separating Growth From Production
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Solution Overview
Problem
Current methods for producing shikimic acid face challenges such as low content, difficult downstream separation, long time-consuming, and high contamination, necessitating a more efficient production method.
Innovation Solution
Regulating asymmetric cell division in a recombinant strain by expressing target genes that include cytoskeletal protein PopZ and enzymes involved in the shikimic acid pathway, such as DAHP synthase, 3-dehydroquinate synthase, and transketolase, to separate cell growth from shikimic acid production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional microbial fermentation methods are used to produce shikimic acid, then production can be achieved, but the content is low, downstream separation is difficult, and the process is time-consuming with high contamination risk
Solution Approach 1:
The invention divides the bacterial cell into two functional compartments through asymmetric cell division: the old pole cell is dedicated to shikimic acid production while the new pole cell maintains growth functions. This segmentation allows simultaneous optimization of production titer and productivity without mutual interference, resolving the contradiction between high content and high efficiency.
Solution Approach 2:
The invention extracts the shikimic acid production function from the growth function by inducing asymmetric cell division. The old pole cell is specifically programmed to accumulate shikimic acid while the new pole cell continues growth, effectively separating these two functions that previously competed for resources, thereby achieving both high content and high productivity.
2Quantity of substance
If cell growth and shikimic acid production are coupled in the same cells, then metabolic resources are shared, but this limits the maximum achievable shikimic acid content
Solution Approach 1:
By segmenting the cell population into growth-specialized new pole cells and production-specialized old pole cells, the invention eliminates the time loss associated with switching between growth and production phases. Both functions occur simultaneously in different cells, achieving high content accumulation without extending production time.
Solution Approach 2:
The invention extracts the production function from growing cells and relocates it to specialized old pole cells. This extraction allows continuous growth in new pole cells while old pole cells dedicate all resources to shikimic acid accumulation, resolving the trade-off between content and time.
3Quantity of substance
If asymmetric cell division is induced to separate growth and production functions, then shikimic acid accumulation is improved, but the device complexity increases
Solution Approach 1:
The invention employs self-service by utilizing the bacterium's own natural asymmetric cell division mechanism (normally observed in Caulobacter but not E. coli) and redirecting it through genetic engineering of specific genes (popZ, parA, parB). The system serves itself by using its inherent division asymmetry for production purposes, reducing the need for complex external control systems while achieving high content accumulation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The recombinant strain achieves high shikimic acid production of 88.1 g/L, with a yield of 0.33 g/g and a production intensity of 1.1 g/L/h, significantly surpassing previous Escherichia coli-based productions.
Implementation Method 1
A cytoskeletal protein is used to regulate asymmetric cell division, and regulate different cell functions. By introducing asymmetrical division of targeted cells, the cell growth is separated from shikimic acid production to allow more shikimic acid to be accumulated.
Implementation Method 2
phosphoenolpyruvate and erythrose-4-phosphate as starting compounds are condensed to form 3-deoxy-D-arabinoheptulosonate-7-phosphate in the presence of 3-deoxy-D-arabinoheptulosonate-7-phosphate (DAHP) synthase
Implementation Method 3
DAHP is catalyzed by 3-dehydroquinate (DHQ) synthase to produce 3-dehydroquinate
Implementation Method 4
DHQ is then converted into 3-dehydroshikimic acid (DHS) in the presence of 3-dehydroquinate dehydratase
Implementation Method 5
DHS is converted into shikimic acid (SA) in the presence of shikimate dehydratase
Data Source
AI summary
The present invention relates to a recombinant strain for producing shikimic acid, in which a target gene that regulates the asymmetric cell division and target genes that regulate the shikimic acid production are expressed The target gene that regulates the asymmetric cell division includes cytoskeletal protein PopZ coding gene popZ, and the target genes that regulate the shikimic acid production include DAHP synthase coding gene aroG, 3-dehydroquinate synthase coding gene aroB, and transketolase coding gene tktA. The recombinant strain of the present invention realizes the de novo synthesis of shikimic acid using glucose as a substrate, with a low cost. After fermentation with the strain in a 7.5 L fermentor, the highest production of shikimic acid is 88.1 g/L, the yield is 0.33 g/g, and the production intensity of shikimic acid is 1.1 g/L/h.