Reverse Beta-Oxidation Cycle for Hydrocarbon Synthesis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The fatty acid biosynthesis pathway is inefficient for producing hydrocarbons and other products due to high ATP consumption in synthesizing malonyl-ACP, limiting cell growth and product yield.
Innovation Solution
A reverse beta-oxidation cycle is driven using CoA thioester intermediates and acetyl-CoA for acyl-chain elongation, combined with type II fatty acid synthesis enzymes like thiolases, 3-oxoacyl-[acyl-carrier-protein] reductases, and enoyl-[acyl-carrier-protein] reductases to produce alcohols, carboxylic acids, and hydrocarbons without the energy-intensive decarboxylative condensation step.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the fatty acid biosynthesis pathway is used to produce hydrocarbons, then hydrocarbon production is achieved, but ATP consumption is high due to malonyl-ACP synthesis
Solution Approach 1:
The patent inverts the conventional fatty acid biosynthesis pathway by using beta-oxidation enzymes in reverse. Instead of synthesizing fatty acids from acetyl-CoA via malonyl-ACP (which consumes ATP), the system uses thiolases, dehydratases, and reductases to elongate acyl chains from acetyl-CoA directly, bypassing the energy-intensive malonyl-ACP synthesis step and enabling hydrocarbon production with reduced ATP consumption
Solution Approach 2:
The patent changes the biochemical parameters of the pathway by substituting enzymes: using beta-oxidation enzymes (thiolases, enoyl-CoA hydratases, hydroxyacyl-CoA dehydrogenases) instead of fatty acid synthesis enzymes (acetyl-CoA carboxylase, malonyl-CoA reductase). This enzyme substitution alters the energy metabolism parameters, eliminating the need for ATP-dependent malonyl-ACP synthesis while maintaining hydrocarbon production capability
2Productivity
If the fatty acid biosynthesis pathway is used, then hydrocarbon synthesis is possible, but cell growth is limited due to low ATP yield
Solution Approach 1:
By reversing the beta-oxidation pathway, the system maintains the ability to synthesize hydrocarbons while improving cellular energy status. The inverted pathway uses acetyl-CoA directly for chain elongation without requiring ATP-dependent activation, thereby increasing net ATP yield and supporting both cell growth and hydrocarbon production simultaneously
3Ease of manufacture
If traditional fatty acid synthesis enzymes are used, then fatty acids can be produced, but energy-intensive decarboxylative condensation steps are required
Solution Approach 1:
The patent extracts and removes the energy-intensive decarboxylative condensation step (catalyzed by acetyl-CoA carboxylase forming malonyl-ACP) from the pathway. By using thiolases to catalyze direct condensation of acetyl-CoA with acyl-CoA intermediates, the system eliminates the need for ATP-dependent carboxylation and decarboxylation steps, reducing energy consumption while maintaining fatty acid/hydrocarbon production
Solution Approach 2:
The patent uses a copy of the beta-oxidation pathway (which naturally operates in the opposite direction) to achieve fatty acid synthesis. By utilizing the reverse of the degradation pathway, the system achieves synthesis without requiring the energy-intensive forward pathway enzymes, effectively copying the enzymatic machinery for a different purpose
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 enables efficient synthesis of hydrocarbons and other products by bypassing the energy-intensive steps of traditional fatty acid biosynthesis, improving cell growth and product yield while allowing for the production of diverse, non-native compounds with minimal foreign genes.
Implementation Method 1
a combination of thiolases with one or more of 3-oxoacyl-[acyl-carrier-protein] reductase
Implementation Method 2
3-oxoacyl-[acyl-carrier-protein] reductase (FabG, others)
Implementation Method 3
3-hydroxyacyl-[acp] dehydratase (FabA, FabZ, others)
Implementation Method 4
enoyl-[acyl-carrier-protein] reductase (FabI, FabK, FabL, FabV, others)
Data Source
AI summary
This disclosure describes enzymes from the type II (a discrete set of enzymes) fatty acid synthesis (“FAS”) pathway that can be used in combination with thiolases to operate a functional reversal of the β-oxidation cycle. A combination of thiolases with one or more of 3-oxoacyl-[acyl-carrier-protein] reductase (FabG, others), 3-hydroxyacyl-[acp] dehydratase (FabA, FabZ, others), and enoyl-[acyl-carrier-protein] reductase (FabI, FabK, FabL, FabV, others) yields a functional reversal of the β-oxidation cycle. If only one or two enzymes are used, the remaining enzymes will be traditional beta oxidation enzymes. Once this cycle is coupled with the appropriate priming and termination pathways, the production of carboxylic acids, alcohols, hydrocarbons, amines and their α-, β-, and ω-functionalized derivatives from renewable carbon sources can be achieved.