Rumen Bacterial Mutant Succinic Acid Production
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Solution Overview
Problem
Current succinic acid production through microbial fermentation has low productivity and is hindered by the production of various organic acids as byproducts, leading to high costs and inefficient separation processes.
Innovation Solution
A rumen bacterial mutant, Mannheimia succiniciproducens PALK, is developed by disrupting genes encoding lactate dehydrogenase, phosphotransacetylase, and acetate kinase, while maintaining pyruvate formate lyase, to produce succinic acid at high concentrations with minimal byproducts in anaerobic conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional microbial fermentation methods are used to produce succinic acid, then succinic acid can be produced, but productivity is low and various organic acids are produced as byproducts
Solution Approach 1:
The patent applies the 'Taking out' principle by removing specific genes (ldhA, pta, ackA) that are responsible for producing unwanted byproducts (lactic acid, acetic acid). By extracting and eliminating these harmful genetic elements from the Mannheimia succiniciproducens genome, the fermentation process produces predominantly succinic acid with minimal byproducts, thus resolving the contradiction between productivity and byproduct formation
Solution Approach 2:
The patent applies 'Parameter changes' by modifying the genetic parameters of the microorganism through gene disruption. By changing the genetic composition (removing ldhA, pta, ackA genes) while maintaining other essential genes like pfl, the metabolic pathway is redirected to favor succinic acid production, transforming the fermentation outcome from mixed organic acids to predominantly succinic acid
2Ease of manufacture
If various organic acids are produced during fermentation, then metabolic pathways are active, but separation and purification costs increase
Solution Approach 1:
The patent converts the harmful effect of byproduct formation into a benefit by strategically disrupting genes. The disruption of ldhA, pta, and ackA genes eliminates competing metabolic pathways that produce unwanted organic acids, thereby converting a potentially harmful mixed-acid fermentation into a beneficial homofermentative process that produces mainly succinic acid, greatly simplifying separation and purification
3Object-generated harmful factors
If gene disruptions are performed to reduce byproducts, then byproduct formation decreases, but microbial growth may be affected
Solution Approach 1:
The patent applies 'Local quality' by performing selective and localized gene disruptions only in specific regions of the metabolic pathway. By disrupting only ldhA (lactate dehydrogenase), pta (phosphotransacetylase), and ackA (acetate kinase) genes while leaving other essential genes intact, the modification locally affects only the byproduct formation pathways without compromising overall microbial growth and metabolic functionality
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 mutant strain achieves high succinic acid productivity with reduced byproduct formation, enhancing growth rates and facilitating efficient succinic acid production, thereby addressing the limitations of existing fermentation methods.
Implementation Method 1
Succinic acid can be produced by chemical synthesis and fermentation... producing succinic acid in anaerobic conditions
Data Source
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AI summary
The present invention relates to a rumen bacterial mutant producing homo- succinic acid and a method for producing homo-succinic acid using the same, and more particularly to a rumen bacterial mutant producing succinic acid at a high concentration while producing little or no other organic acids in anaerobic conditions, which is obtained by disrupting a gene encoding lactate dehydrogenase (idhA), a gene encoding phosphotransacetylase (pta), and a gene encoding acetate kinase (ackA), without disrupting a gene encoding pyruvate formate lyase (pß), as well as a method for producing succinic acid using the same. The inventive rumen bacterial mutant has the property of having a high growth rate and succinic acid productivity while producing little or no organic acids, as compared to the prior strains producing succinic acid. Thus, the inventive rumen bacterial mutant is useful to produce succinic acid for industrial use.