Mutant Thioesterase Specificity for Medium-Chain Fatty Acid Production
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Solution Overview
Problem
Current methods for producing biodiesel through transesterification result in heterogeneous products and unwanted by-products, leading to economic inefficiencies and gelation issues at low temperatures due to the presence of methyl and ethyl esters, and existing thioesterases lack specificity for medium-chain fatty acids, requiring costly downstream separation.
Innovation Solution
Development of computationally redesigned thioesterases, such as mutant TesA, which increases the production of medium-chain fatty acids (C8-C14) by enhancing specificity and activity, reducing the need for costly separation processes and improving biodiesel production efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If transesterification method is used for biodiesel production, then biodiesel can be produced from fatty acid precursors, but heterogeneous products and unwanted by-products are generated leading to economic inefficiencies
Solution Approach 1:
The patent changes the biochemical parameters of fatty acid production by introducing mutant thioesterases with specific enzymatic properties. These mutants produce medium-chain fatty acids (C6-C12) with high specificity, altering the chemical composition parameters to eliminate unwanted by-products and improve biodiesel production efficiency through direct hydrolysis of acyl-ACP thioester bonds
Solution Approach 2:
The patent extracts and removes unwanted by-products (methyl and ethyl esters) from the reaction system by using specific thioesterase enzymes that selectively hydrolyze acyl-ACP thioester bonds to produce only free fatty acids. This extraction approach eliminates harmful by-products at the source rather than treating them after formation
2Manufacturing precision
If existing thioesterases are used to control FFA chain length, then some FFA production is achieved, but they lack specificity for medium-chain fatty acids requiring costly downstream separation
Solution Approach 1:
The patent applies local quality by creating thioesterase mutants with specific active site characteristics that are locally optimized for binding and hydrolyzing medium-chain acyl-ACP substrates (C6-C12). Mutants like TesA with specific amino acid sequences at positions 78, 80, 101, 108, 111, 117, 118, 122, 145, 152, and 178 provide localized catalytic specificity that eliminates the need for complex downstream separation processes
3Adaptability or versatility
If broad substrate specificity thioesterases are used, then various FFA compositions can be produced, but costly downstream separation is required to purify specific chain lengths
Solution Approach 1:
The patent changes the substrate specificity parameter of thioesterases through directed mutagenesis, creating enzymes with narrow specificity for medium-chain fatty acids (C6-C12). This parameter change maintains adaptability within the medium-chain range while eliminating the need for costly separation processes by producing a uniform product composition
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 mutant thioesterases achieve significant increases in medium-chain fatty acid production, enhancing biodiesel production efficiency and reducing production costs by minimizing unwanted by-products and gelation issues, thereby improving the economic viability of biodiesel production.
Implementation Method 1
The specificity of the acyl-ACP thioesterase controls the terminal aliphatic chain length and chemical properties of the FFA product composition. The mutant thioesterase catalyzes the hydrolysis of the thioester bond to generate the FFA and ACP.
Implementation Method 2
The mutant thioesterase has at least one altered property in vitro and/or in vivo, as compared to the properties of the precursor thioesterase. The mutant thioesterase catalyzes the hydrolysis of a C8, C10, C12, and/or C14 acyl-acyl carrier protein substrate to yield a free fatty acid.
Data Source
AI summary
Unnatural, mutated thioesterases having an amino acid sequence that is at least 80% identical to SEQ. ID. NO: 1 and having substitutions at one or more of amino acid positions I107, R108, L109, S122, M141, E142, Y145, and L146, gene constructs encoding and configured to express the mutated thioesterases in a transformed host cell and host cells transformed to contain the gene constructs.