Reverse Glyoxylate Shunt for Glycolic Acid Yield
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Solution Overview
Problem
Existing metabolic pathways for producing glycolic acid and glycine result in suboptimal yields due to excess NADH and CO2 production, leading to product loss and inefficient carbon utilization.
Innovation Solution
Development of recombinant microorganisms with a reverse glyoxylate shunt pathway that couples carbon fixation enzymes with reverse glyoxylate shunt enzymes to enhance yield, utilizing CO2 and NAD(P)H, and rerouting carbon flow to increase biosynthesis of glycolic acid and glycine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional glyoxylate shunt pathway is used for glycolic acid and glycine production, then the pathway can produce these valuable compounds, but the yield is suboptimal due to excess NADH and CO2 production causing carbon loss
Solution Approach 1:
The patent inverts the traditional glyoxylate shunt pathway to create a reverse glyoxylate shunt pathway. Instead of the conventional direction that produces excess CO2 and NADH, the reversed pathway uses CO2 and NAD(P)H as substrates to produce glycolic acid and glycine, thereby converting harmful byproducts into valuable products and eliminating carbon loss.
Solution Approach 2:
The patent converts the harmful effects of excess CO2 and NADH production into beneficial outcomes. By designing the reverse pathway to consume these excess compounds as reactants, the previously wasted carbon and energy are now utilized productively to synthesize glycolic acid and glycine, transforming a metabolic burden into a production advantage.
2Quantity of substance
If carbon fixation enzymes are coupled with reverse glyoxylate shunt enzymes, then the theoretical yield of glycolic acid and glycine increases, but the pathway complexity increases
Solution Approach 1:
The patent merges carbon fixation enzymes with reverse glyoxylate shunt enzymes into a integrated biosynthetic pathway. This combination allows the pathway to simultaneously perform carbon fixation and glycolic acid/glycine synthesis, achieving high theoretical yield while maintaining pathway efficiency through enzymatic coordination.
Solution Approach 2:
The reverse glyoxylate shunt pathway serves multiple functions: it acts as both a carbon fixation route and a biosynthetic pathway for glycolic acid and glycine production. This multi-functionality allows the system to achieve high yield while managing complexity through unified pathway design rather than separate independent pathways.
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 approach significantly improves the yield of glycolic acid and glycine by reducing carbon loss and optimizing carbon fixation, achieving higher theoretical yields compared to traditional pathways.
Implementation Method 1
a gene encoding malate dehydrogenase that catalyzes the conversion of pyruvate to malate
Implementation Method 2
a gene encoding malate thiokinase that catalyzes the conversion of malate to malyl coenzyme A
Implementation Method 3
a gene encoding malyl coenzyme A lyase that catalyzes the conversion of malyl coenzyme A to glyoxylate and acetyl-CoA
Data Source
AI summary
The present invention provides biochemical pathways, glyoxylate producing recombinant microorganisms, and methods for the production and yield improvement of glycolic acid and/or glycine via a reverse glyoxylate shunt. The reverse glyoxylate shunt comprises an enzyme that catalyzes the carboxylation of phosphoenol pyruvate (PEP) to oxaloacetate (OAA), or an enzyme that catalyzes the carboxylation of pyruvate to oxaloacetate (OAA) or an enzyme that catalyzes the carboxylation of pyruvate to malate or a combination of any of the previous reactions; an enzyme that catalyzes the conversion of malate to malyl-CoA; an enzyme that catalyzes the conversion of malyl-CoA to glyoxylate and acetyl-CoA; and optionally an enzyme that catalyzes the conversion of oxaloacetate (OAA) to malate. Glyoxylate is reduced to produce glycolate. Alternatively, glyoxylate is converted to glycine. The reverse glyoxylate shunt pathway of the present invention can be utilized synergistically with other glycolic acid and/or glycine producing pathways to increase product yield.