Recombinant Microorganism Pathway for MEG from Pentose and Hexose Sugars

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Solution Overview

Problem

Current methods for producing monoethylene glycol (MEG) and glycolic acid from sugars face challenges such as low yield potential, ATP shortage, excess NADH, and inefficient use of D-xylose due to market limitations and glucose-induced inhibition, leading to suboptimal production efficiencies.

Innovation Solution

A recombinant microorganism is engineered with a biochemical pathway that converts pentose and hexose sugars into glyceraldehyde-3-phosphate and glycolaldehyde through a pentose-phosphate intermediate using enzymes like pentose-phosphate aldolase, transketolase, and ribulokinase, allowing for high-yield production of MEG and glycolic acid without carbon loss, and enabling the use of D-glucose and D-xylose with improved efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional biosynthetic pathways are used to produce MEG from sugars, then MEG production is achieved, but product yield is low and ATP shortage occurs

Engineering Contradiction:

ImproveMEG production yieldVSAvoidATP availability

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The biosynthetic pathway is segmented into distinct modular stages: sugar uptake and phosphorylation, isomerization to pentose phosphates, aldolase cleavage to glycolaldehyde and G3P, and final MEG synthesis. This modular segmentation allows independent optimization of each stage to improve overall yield and energy efficiency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The pathway uses key intermediary compounds (pentose phosphates, glycolaldehyde, glyceraldehyde-3-phosphate) as metabolic hubs that connect sugar catabolism to MEG synthesis. These intermediaries enable efficient carbon flow and redox balancing, resolving the ATP shortage problem by creating a more energy-efficient pathway.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If conventional pathways are used, then MEG is produced, but carbon loss occurs reducing overall efficiency

Engineering Contradiction:

ImproveMEG production efficiencyVSAvoidCarbon loss

Core Design Contradiction:

ProductivityVSLoss of substance

Solution Approach 1:

The pathway changes the metabolic parameters by using non-oxidative pentose phosphate pathway enzymes (transketolase, transaldolase) instead of conventional oxidative pathways. This parameter change eliminates decarboxylation steps that cause carbon loss, achieving near-theoretical maximum carbon conversion efficiency to MEG.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If D-xylose is used as substrate, then additional carbon source utilization is achieved, but glucose-induced inhibition reduces efficiency

Engineering Contradiction:

ImproveSugar substrate utilizationVSAvoidD-xylose conversion efficiency

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The pathway employs preliminary phosphorylation of D-xylose to D-xylose-5-phosphate by xylose kinase, and isomerization to D-xylulose-5-phosphate by xylose isomerase, before entering the main pentose phosphate pathway. This preliminary processing prepares D-xylose for efficient metabolism and reduces the inhibitory effect of glucose by creating a dedicated entry point for pentose utilization.

Inventive Principle:

Principle #10Preliminary action

4Productivity

If engineered pathways are implemented, then MEG production capability is achieved, but excess NADH accumulation creates redox imbalance

Engineering Contradiction:

ImproveBiosynthetic capabilityVSAvoidRedox balance

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The pathway converts the potential harm of excess NADH accumulation into a benefit by coupling NADH-consuming reactions (glycolaldehyde reduction to MEG, G3P metabolism) with NADH-generating reactions (sugar phosphorylation, pentose phosphate pathway). This redox balancing transforms the metabolic burden into a self-regulating system that maintains redox homeostasis while producing MEG.

Inventive Principle:

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

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 achieves redox-neutral high-yield production of MEG and glycolic acid, overcoming previous limitations by utilizing a non-oxidative pentose phosphate pathway that minimizes carbon loss and ATP shortage, and allows for efficient co-production with other valuable compounds like acetone and serine pathway products.

Implementation Method 1

introducing just one new reaction catalyzed by a pentose-phosphate aldolase

Methodology Applied

Scientific EffectAldolase reaction: Chemical Bonding

Implementation Method 2

using enzymes like pentose-phosphate aldolase, transketolase, and ribulokinase

Methodology Applied

Scientific EffectTransketolase reaction: Chemical Bonding

Implementation Method 3

using enzymes like pentose-phosphate aldolase, transketolase, and ribulokinase

Methodology Applied

Scientific EffectKinase reaction: Chemical Bonding

Data Source

PatentUS11584944B2Degradation pathway for pentose and hexose sugars

Publication Date: 2023.02.21 BRASKEM SA

AI summary

The present application relates to recombinant microorganisms useful in the biosynthesis of monoethylene glycol (MEG) or glycolic acid (GA), or MEG and one or more co-product, from one or more pentose and/or hexose sugars. Also provided are methods of producing MEG (or GA), or MEG (or GA) and one or more co-product, from one or more pentose and/or hexose sugars using the recombinant microorganisms, as well as compositions comprising the recombinant microorganisms and/or the products MEG (or GA), or MEG and one or more co-product.