Mutant IRX10 Enzyme Suppresses Xylan Biosynthesis

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Solution Overview

Problem

The high abundance of xylan in plant biomass poses challenges for biofuel production, as xylose is poorly utilized by microorganisms and inhibits glucose fermentation, and the acetate from the xylan backbone creates a toxic environment for microbial growth, necessitating a reduction in xylan content.

Innovation Solution

A polypeptide with at least 70% identity to the IRX10 enzyme is engineered with specific amino acid substitutions to dominate the xylan biosynthesis pathway, reducing xylan production by overexpressing the mutated enzyme, which competes with the native form and suppresses xylan biosynthesis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If xylan is present in high amounts in plant biomass, then the plant structure and mechanical strength are maintained, but the conversion efficiency to biofuel is reduced due to microbial inhibition and poor xylose utilization

Engineering Contradiction:

Improvebiofuel conversion efficiencyVSAvoidmicrobial inhibition

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the chemical parameters of xylan by introducing mutant IRX10 enzymes with modified amino acid sequences that alter xylan biosynthesis. These parameter changes in the enzyme structure lead to reduced xylan production and modified xylan composition, thereby improving biofuel conversion efficiency by reducing microbial inhibition

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention converts the harmful effect of xylan (microbial inhibition) into a benefit by using the IRX10 enzyme system to selectively reduce xylan content. The mutant enzymes suppress xylan biosynthesis while maintaining plant viability, transforming the problem of high xylan content into an opportunity for improved biofuel production

Inventive Principle:

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

2Productivity

If xylan biosynthesis is suppressed to reduce xylan content, then biofuel conversion efficiency is improved, but plant structural integrity and mechanical strength may be compromised

Engineering Contradiction:

Improvebiofuel conversion efficiencyVSAvoidplant mechanical strength

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The invention applies local quality by using tissue-specific promoters to drive expression of mutant IRX10 enzymes in specific plant tissues where xylan reduction is desired for biofuel production, while maintaining normal xylan biosynthesis in tissues requiring structural integrity. This spatial differentiation allows selective suppression of xylan in non-structural tissues

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention employs partial action by using mutant IRX10 enzymes that partially suppress xylan biosynthesis rather than completely eliminating it. This partial suppression reduces xylan content to optimal levels for biofuel conversion while maintaining sufficient xylan for plant structural requirements

Inventive Principle:

Principle #16Partial or excessive action

3Productivity

If mutant IRX10 enzymes are overexpressed to dominate the xylan biosynthesis pathway, then xylan production is reduced, but the complexity of genetic modification and enzyme engineering increases

Engineering Contradiction:

Improvexylan suppression efficiencyVSAvoidgenetic modification complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The invention achieves universality by developing mutant IRX10 enzymes that can function across different plant species and tissue types. The engineered enzymes maintain catalytic activity and suppression efficiency across diverse biological systems, reducing the need for species-specific optimization and simplifying the overall genetic modification process

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention applies preliminary action by pre-engineering the IRX10 enzyme with specific amino acid mutations that are predicted to enhance suppression efficiency before deployment. This preliminary optimization of enzyme structure reduces the complexity of subsequent genetic modification by eliminating the need for extensive trial-and-error testing in target plants

Inventive Principle:

Principle #10Preliminary action

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

This approach effectively decreases xylan content in plants, enhancing the conversion efficiency of plant biomass to biofuel by improving microbial tolerance and sugar yield during saccharification reactions.

Implementation Method 1

IRX10 is a putative xylan biosynthetic enzyme... overexpression of the mutated IRX10 outcompetes the native form of the enzyme, suppressing the biosynthesis of the polymer

Methodology Applied

Scientific EffectEnzyme catalysis: Enzyme

Data Source

PatentUS11208666B2Mutant xylan biosynthetic enzymes capable of dominant suppression of xylan biosynthesis

Publication Date: 2021.12.28 RGT UNIV OF CALIFORNIA

AI summary

The present invention provides for a polypeptide capable of dominant suppression of a first naturally occurring IRX10, wherein the polypeptide comprises an amino acid sequence having at least 70% identity as compared to a second naturally occurring IRX10 wherein the polypeptide comprises one or more of the conserved amino acid indicated in FIG. 2 substituted with a different amino acid residue.