Recombinant Microorganism Butanol Production Pathway Optimization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for producing butanol using microorganisms face challenges in achieving high selectivity, yield, and productivity, with existing recombinant strains exhibiting limitations in growth inhibition, increased acetic acid production, and low final butanol concentrations.
Innovation Solution
A recombinant microorganism is developed by deleting genes related to butyrate and acetate production (pta and buk) and co-overexpressing CtfAB and adhE genes to promote the conversion of butyryl-CoA to butanol, thereby enhancing butanol production pathways and suppressing unwanted conversions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If pta and buk genes are deleted to enhance butanol selectivity, then butanol yield is improved, but productivity is reduced due to growth inhibition
Solution Approach 1:
The patent applies parameter changes by modifying gene expression levels rather than simply deleting genes. Specifically, it optimizes the expression of ctfAB and adhE genes to redirect metabolic flux toward butanol production while maintaining cell growth, thereby resolving the contradiction between yield and productivity through quantitative genetic modification rather than qualitative gene deletion
Solution Approach 2:
The patent employs dynamic metabolic pathway regulation by controlling the expression levels of key enzymes at different growth phases. The system dynamically balances cell growth and butanol production by regulating ctfAB and adhE expression, allowing the microorganism to transition smoothly from growth mode to production mode, thus maintaining both productivity and yield
2Quantity of substance
If co-overexpression of adhE1 and ctfAB genes is performed to enhance butanol selectivity, then butanol selectivity is improved, but productivity and yield are reduced due to growth inhibition
Solution Approach 1:
The patent applies parameter changes by precisely controlling the expression levels of ctfAB and adhE genes. Instead of strong constitutive overexpression that inhibits growth, the system uses optimized expression levels that maintain metabolic flux toward butanol while preserving cell viability and growth rate, thereby achieving high selectivity without sacrificing productivity
Solution Approach 2:
The patent applies partial action by selectively overexpressing only the necessary genes (ctfAB and adhE) at optimized levels rather than complete pathway overexpression. This partial genetic modification is sufficient to redirect metabolic flux toward butanol production without causing the severe growth inhibition that results from more aggressive overexpression strategies
3Quantity of substance
If pta and buk genes are deleted to increase butanol concentration, then butanol selectivity is improved, but strain stability is reduced
Solution Approach 1:
The patent applies parameter changes by using gene expression optimization instead of gene deletion. By controlling the expression levels of ctfAB and adhE genes, the system achieves high butanol concentration while maintaining the完整性 of the metabolic network, which preserves strain stability and prevents the metabolic imbalances that arise from gene deletions
4Quantity of substance
If CtfB gene is deleted from pta and buk deleted strain to enhance butanol selectivity, then butanol selectivity is improved, but productivity remains low
Solution Approach 1:
The patent applies parameter changes by optimizing the expression of remaining CoA transferase activity through ctfA gene and other compensatory pathways. Instead of completely deleting ctfB, the system balances CoA transferase activity to maintain butyrate suppression while preserving sufficient metabolic flexibility for high productivity
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 microorganism demonstrates improved butanol productivity, yield, and selectivity, with increased butanol production up to 28% yield and 1.3 g/L/h productivity, making it suitable for industrial applications.
Implementation Method 1
methods for producing butanol, acetone and ethanol by fermenting sugars with Clostridium strains were utilized as typical methods for preparing butanol
Data Source
AI summary
The present invention relates to a microorganism having an acetyl CoA biosynthesis pathway and a butyryl CoA biosynthesis pathway; the microorganism being a recombinant microorganism having an increased ability to produce butanol, wherein a pathway for converting acetyl CoA into acetate is suppressed, and a pathway for converting acetate into acetyl CoA and a pathway for converting butyryl CoA into butanol are promoted. Also, the present invention concerns a method for producing butanol by using the recombinant microorganism.