E. coli Transformant with Disrupted Efflux Pumps for Enhanced Bioconversion
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Solution Overview
Problem
Current microbial conversion methods using E. coli to produce pharmaceutical compounds face low conversion efficiency due to the host's ability to metabolize or degrade substrate compounds and products, and the need for coenzymes, which are costly and require enzyme stabilization.
Innovation Solution
Creating a transformant by introducing a gene from a xenogeneic organism into an E. coli host defective in multidrug efflux protein genes, such as tolC, acrA, or acrB, to enhance the expression and retention of cytochrome P-450 enzymes, thereby improving substrate conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If microbial conversion is performed using E. coli to produce pharmaceutical compounds, then enzyme activity can be retained continuously through cellular metabolism, but conversion efficiency is low due to host metabolism degrading substrate compounds and products
Solution Approach 1:
The patent applies this principle by disrupting the multidrug efflux pump system (which normally protects E. coli by exporting toxic substances) and converting this harmful defense mechanism into a beneficial feature. The disrupted efflux pump fails to export substrate compounds and products, causing them to accumulate intracellularly and thereby improving conversion efficiency while maintaining continuous enzyme activity through cellular metabolism.
Solution Approach 2:
The patent extracts and removes the functional multidrug efflux pump genes (tolC, acrA, acrB) from the E. coli genome through targeted disruption. By taking out this specific genetic component responsible for substrate degradation, the patent eliminates the harmful metabolic pathway while preserving the rest of the cellular metabolism needed for continuous enzyme activity production.
2Productivity
If multidrug efflux pump genes are disrupted to prevent substrate degradation, then conversion efficiency increases, but cellular resistance to toxic substances is reduced
Solution Approach 1:
The patent converts the harmful efflux pump function (which exports substrates and reduces conversion efficiency) into a beneficial feature by disrupting it. The same pump that normally protects the cell is now disabled, allowing substrates to accumulate intracellularly and improve conversion efficiency, while the cell's other defense mechanisms remain intact.
3Manufacturing precision
If cytochrome P-450 enzymes are expressed in E. coli for pharmaceutical production, then regiospecific and stereosspecific modifications can be achieved, but coenzymes are required which are expensive and require stabilization
Solution Approach 1:
The patent applies self-service by enabling the E. coli host's own metabolic system to continuously produce and regenerate the required coenzymes (NADPH, ATP) through its central metabolism. This eliminates the need for external coenzyme addition and stabilization, as the cell serves itself by regenerating coenzymes through its natural metabolic pathways while maintaining the cytochrome P-450 enzyme's regiospecific and stereosspecific modification capabilities.
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 method significantly increases the conversion efficiency of hydrophobic and amphipathic compounds, such as vitamin D3 and compactin, by preventing their degradation and reducing the need for coenzymes, leading to higher yields and cost-effectiveness in pharmaceutical production.
Implementation Method 1
a host which is defective in multidrug efflux protein
Implementation Method 2
The P-450 enzyme is involved in, as specific functions, a wide variety of reactions such as xenobiotic hydroxylation, epoxidation, dealkylation and denitrogenation within the cells exhibiting the P-450 enzymes by catalyzing the monooxygenation
Implementation Method 3
These P-450 enzymes originated from the microorganism can catalyze the monooxygenation only by conjugating with the electron transport system (ferredoxin and ferredoxin reductase) which donates electrons to the enzymes
Data Source
AI summary
Disclosed is a means for improving the poor conversion efficiency in a conventional bioconversion system using a transformant which is given by introducing a gene originated from xerogenic organisms. A transformant is prepared by using a host which is defective in a gene encoding a multidrug efflux protein and introducing a gene originated from xerogenic organisms. Use of the transformant results in much effective microbial conversion of a hydrophobic or amphipathic substrate compound into a desired compound. In case, an Escherichia coli is used as the host, the gene encoding a multidrug efflux protein to be defective may be tolC, acrA, acrB and the like.