Isovaleryl Spiramycin I Production via acyB2 Regulatory Gene Integration
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Solution Overview
Problem
Current production methods for Bitespiramycin, a multi-component antibiotic, face challenges in achieving high yield and consistent content of the single component isovaleryl spiramycin I due to limitations in gene modification and quality control, making large-scale production and development of injectable formulations complex.
Innovation Solution
A genetically engineered Streptomyces strain, WSJ-IA, is developed by co-expressing the isovaleryl transferase gene (ist) linked with the acyB2 regulatory gene using a non-autonomous replication vector, enhancing the production and content of isovaleryl spiramycin I through improved gene expression and integration in the bacterium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the ist gene is introduced into Streptomyces to produce isovaleryl spiramycin, then the antibiotic production capability is improved, but the fermentation titer and component content remain low
Solution Approach 1:
The patent combines the ist gene (isovaleryl transferase) with the acyB2 regulatory gene into a single expression cassette. The acyB2 gene encodes a transcriptional activator that specifically activates ist gene expression. This merging ensures coordinated expression where the regulatory gene enhances the productivity of the antibiotic synthesis gene, resolving the contradiction between production capability and actual yield.
Solution Approach 2:
The patent modifies the expression parameters by introducing the acyB2 regulatory gene that controls the transcriptional activity of ist. This changes the expression level parameter from low (when only ist is present) to high (when acyB2 activates ist), thereby increasing both fermentation titer and component content while maintaining the antibiotic production capability.
2Reliability
If multi-component Bitespiramycin is produced, then antibiotic activity is achieved, but quality control and purification processes become complex
Solution Approach 1:
The patent extracts and isolates the specific gene pathway responsible for producing the desired isovaleryl spiramycin component by introducing only the ist gene with acyB2 regulation. This eliminates the need for complex multi-component production, allowing for simplified quality control and purification processes while maintaining reliable antibiotic activity through targeted single-component production.
3Manufacturing precision
If gene modification is performed to increase isovaleryl spiramycin I content, then single component purity is improved, but fermentation yield decreases
Solution Approach 1:
The patent implements a feedback mechanism through the acyB2 regulatory gene, which encodes a transcriptional activator that responds to cellular conditions and enhances ist gene expression. This feedback loop ensures that as the bacteria grow and metabolize, the expression of isovaleryl spiramycin is upregulated, simultaneously improving both single component content and fermentation yield rather than sacrificing one for the other.
Solution Approach 2:
The patent performs preliminary genetic engineering by pre-combining the ist gene with the acyB2 regulatory gene in the plasmid construct before introduction into Streptomyces. This preliminary setup ensures that from the outset, the bacteria are programmed to produce high levels of isovaleryl spiramycin I with both high purity and high yield, avoiding the need for subsequent modifications that might compromise either parameter.
Data Source
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Figure 3A~3B
AI summary
A genetically engineered strain WSJ-IA for producing isovaleryl spiramycin I. Also provided is a method for preparing the strain, comprising the steps of: (a) constructing a recombinant plasmid comprising a double gene ist-acyB2; (b) transforming the plasmid into an isovaleryl spiramycin I - producing strain to obtain the strain WSJ-IA. The level of isovaleryl spiramycin I produced by fermentation of the strain WSJ-IA is increased 1.7 times and the fermentation potency thereof increased 4.14 times in comparison with the strain exclusively comprising a single gene ist.