Rhizopus Mutant Reducing Pyruvate Decarboxylase Activity

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Solution Overview

Problem

The genetic background of fungi from the genus Rhizopus is not fully understood, making it challenging to develop strains suitable for efficient organic acid production using gene recombination techniques, despite methods like disrupting the pyruvate decarboxylase gene or suppressing its activity being explored for improving productivity.

Innovation Solution

A mutant of the genus Rhizopus with reduced pyruvate decarboxylase activity is created by modifying the pdc gene, either by deleting or inactivating it, using techniques such as siRNA, PDC inhibitors, or genome editing with programmable nucleases like TALEN, to enhance organic acid production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If gene recombination techniques are used to improve organic acid productivity in Rhizopus, then productivity can be enhanced, but the genetic background of Rhizopus is not fully understood making it difficult to apply these techniques effectively

Engineering Contradiction:
Improveorganic acid productivityVSAvoidease of strain development
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The patent extracts and targets the specific pyruvate decarboxylase gene (pdc gene) from the complex Rhizopus genetic background. By focusing on this single gene responsible for ethanol production, the invention simplifies the genetic modification process despite the overall complexity of Rhizopus genetics, enabling effective strain development through targeted gene disruption or expression suppression

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the expression level parameter of the pdc gene by applying gene recombination techniques such as promoter replacement, gene disruption, or RNA interference. This parameter change directly reduces pyruvate decarboxylase activity and ethanol production while enhancing organic acid productivity, resolving the contradiction between improving productivity and dealing with genetic complexity

Inventive Principle:
Principle #35Parameter changes

2Productivity

If pyruvate decarboxylase activity is reduced to improve fumaric acid productivity, then fumaric acid yield increases, but by-product ethanol production must be controlled

Engineering Contradiction:
Improvefumaric acid productivityVSAvoidethanol by-product
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful effect of pyruvate decarboxylase activity (ethanol by-product formation) into a benefit by selectively suppressing this enzyme's function. By disrupting or downregulating the pdc gene, the invention redirects metabolic flux away from ethanol production and toward fumaric acid accumulation, transforming a harmful by-product pathway into an opportunity for improved target product yield

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent extracts and specifically targets the pyruvate decarboxylase enzyme function from the overall metabolic network of Rhizopus. By applying gene disruption or expression suppression techniques to the pdc gene, the invention removes the ethanol-producing pathway while preserving and enhancing the fumaric acid production pathway, thereby improving productivity while controlling harmful by-products

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentUS10947522B2Mutant of genus <i>Rhizopus</i>
Publication Date: 2021.03.16 KAO CORP

AI summary

The present invention provides a fungus of the genus Rhizopus having high productivity of an organic acid. The present invention also provides a mutant of the genus Rhizopus with reduced pyruvate decarboxylase activity.