Schizosaccharomyces pombe Transformant for Lactic Acid Production
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Solution Overview
Problem
Current methods for producing lactic acid, such as using lactic acid bacteria, face challenges with low productivity and require neutralization with alkali, making the process complex and costly, while existing transformants using Saccharomyces cerevisiae are not suitable for industrial-scale production without alkali neutralization.
Innovation Solution
A transformant of Schizosaccharomyces pombe is developed by introducing a lactate dehydrogenase gene and deleting or inactivating part of the pyruvate decarboxylase gene cluster, allowing for high productivity of L-lactic acid without alkali neutralization, suitable for high sugar concentrations and high-density fermentation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If lactic acid bacteria are used for fermentation, then lactic acid can be produced biologically, but the productivity is low and neutralization with alkali is required
Solution Approach 1:
The invention changes the host organism from lactic acid bacteria to Schizosaccharomyces pombe transformant, fundamentally altering the biological system parameters. This enables the organism to tolerate high lactic acid concentrations without requiring alkali neutralization, thereby simplifying the process and improving productivity
Solution Approach 2:
The transformant allows direct production of L-lactic acid that can be recovered without expensive neutralization steps. The system uses a robust organism that can withstand acidic conditions, eliminating the need for costly alkali addition and subsequent recovery processes
2Device complexity
If Saccharomyces cerevisiae transformant is used, then alkali neutralization is avoided, but the transformant is not suited for industrial mass production
Solution Approach 1:
Instead of using Saccharomyces cerevisiae which lacks acid tolerance, the invention inverts the approach by selecting Schizosaccharomyces pombe, a fission yeast known for its superior acid resistance. This inversion enables the organism to thrive in high lactic acid environments, making it suitable for industrial-scale production without neutralization
Solution Approach 2:
The invention changes the yeast species from Saccharomyces cerevisiae to Schizosaccharomyces pombe, fundamentally altering the biological parameters. S. pombe exhibits higher acid tolerance and can maintain productivity under high lactic acid concentrations, enabling industrial-scale production without alkali neutralization
3Productivity
If pyruvate decarboxylase activity is present, then ethanol fermentation occurs, but lactic acid productivity is reduced
Solution Approach 1:
The invention extracts or removes the pyruvate decarboxylase gene from the Schizosaccharomyces pombe genome. By eliminating this gene, the organism cannot perform ethanol fermentation via the pyruvate decarboxylase pathway, thereby directing all pyruvate flux toward L-lactic acid production and maximizing productivity
Solution Approach 2:
The invention discards the pyruvate decarboxylase gene functionality by deletion. This eliminates the competing ethanol fermentation pathway, ensuring that pyruvate is exclusively converted to L-lactic acid by the introduced lactate dehydrogenase enzyme, thereby recovering maximum lactic acid 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 Schizosaccharomyces pombe transformant achieves high productivity of L-lactic acid without the need for alkali neutralization, is suitable for high sugar concentrations, and supports high-density fermentation, simplifying the production process and reducing costs.
Implementation Method 1
introducing a gene encoding a lactate dehydrogenase into the acid resistant microorganism
Implementation Method 2
producing lactic acid by fermenting a sugar by a lactic acid bacterium
Data Source
AI summary
The present invention relates to a transformant, containing a lactate dehydrogenase gene which is introduced into Schizosaccharomyces pombe as a host, in which a part of a gene cluster encoding a pyruvate decarboxylase in the Schizosaccharomyces pombe host is deleted or inactivated.