Yeast Cell Wall Integrity Pathway Engineering for Butanol Tolerance

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Yeast cells used in butanol production are limited by butanol toxicity, leading to low yield and sensitivity, necessitating the development of strains with increased tolerance and improved biosynthetic pathways for efficient butanol production.

Innovation Solution

Recombinant yeast cells engineered with a butanol biosynthetic pathway and genetic modifications that enhance the activity of the cell wall integrity pathway, specifically overexpressing SLT2 protein encoding genes to increase tolerance to butanol, thereby improving growth yield and production efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If yeast cells are used for butanol production, then butanol can be produced through fermentation, but butanol toxicity limits growth yield and production efficiency

Engineering Contradiction:

Improvebutanol production efficiencyVSAvoidbutanol toxicity to yeast

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by modifying the yeast cell's physiological state through genetic engineering. Specifically, it overexpresses genes involved in the cell wall integrity pathway (such as PKC1, BCK1, MKK1, MKK2, SLT2, and SWE1) to alter the cell's response to butanol stress, thereby changing its tolerance parameters and enabling higher productivity in the presence of butanol

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the harmful effect of butanol toxicity into a beneficial outcome by engineering yeast strains that respond to butanol stress through enhanced cell wall integrity pathways. The butanol stress that would normally inhibit growth is instead used to trigger protective mechanisms (via MAP kinase signaling) that ultimately improve the cell's ability to tolerate and produce butanol at higher levels

Inventive Principle:

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

2Productivity

If yeast strains with increased butanol tolerance are developed through genetic engineering, then butanol production efficiency improves, but the complexity of the yeast strain increases

Engineering Contradiction:

Improvebutanol production yieldVSAvoidyeast strain genetic complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the complex problem of butanol tolerance into specific manageable components by targeting individual genes and signaling pathways. Rather than attempting to engineer overall tolerance through multiple unrelated modifications, it focuses on specific segments of the cell's stress response system (the cell wall integrity pathway genes), making the genetic engineering process more systematic and controllable

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent exploits the universality of the cell wall integrity pathway, which serves multiple functions including maintaining cell structure, responding to environmental stress, and regulating growth. By enhancing this universal pathway, the yeast gains improved butanol tolerance as a byproduct of its normal stress response mechanisms, rather than requiring specialized butanol-specific adaptations

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS8795992B2Yeast with increased butanol tolerance involving cell wall integrity pathway

Publication Date: 2014.08.05 GEVO INC

AI summary

Increasing tolerance to butanol in yeast has been accomplished by increasing activity of the cell wall integrity pathway. Yeast with increased expression of SLT2p, a mitogen activated protein kinase of the MAPK module of the cell wall integrity pathway had increased tolerance to isobutanol. These yeast may be used for improved butanol production.