Engineered E. coli for branched-chain fatty acid production
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Solution Overview
Problem
There is a need for commercially viable, bacterially-produced branched-chain fatty acids with specific chain lengths and branch positions, as natural organisms do not produce them in sufficient quantities or with the desired characteristics.
Innovation Solution
Engineering Escherichia coli cells to overexpress specific polynucleotides encoding enzymes that convert propionyl-CoA to methylmalonyl-CoA and succinyl-CoA, allowing for the production of branched-chain fatty acids with methyl branches on even-numbered carbons, using propionyl-CoA carboxylase and methylmalonyl-CoA mutase, and incorporating these enzymes into the fatty acid synthesis pathway.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If natural organisms (Bacillus, Streptomyces) are used to produce branched-chain fatty acids, then some branched-chain fatty acids can be produced, but the production amount is not commercially useful and medium-chain branched-chain fatty acids cannot be produced
Solution Approach 1:
The patent divides the fatty acid synthesis pathway into separate functional modules: propionyl-CoA carboxylase for converting propionyl-CoA to methylmalonyl-CoA, methylmalonyl-CoA mutase for converting methylmalonyl-CoA to succinyl-CoA, and acyl transferase for incorporating methylmalonyl-CoA into fatty acids. This segmentation allows independent optimization of each step to achieve commercial viability and control over medium-chain fatty acid production.
Solution Approach 2:
The patent modifies the metabolic parameters of E. coli by introducing and overexpressing specific enzymes (propionyl-CoA carboxylase, methylmalonyl-CoA mutase) that are not naturally present in high amounts. This changes the flux through the pathway to produce medium-chain branched-chain fatty acids in commercially useful quantities, overcoming the limitations of natural organisms.
2Productivity
If E. coli is used as host cell, then commercially viable production can be achieved, but the cell does not naturally produce branched-chain fatty acids with desired chain lengths and branch positions
Solution Approach 1:
The patent makes E. coli a multi-functional system by introducing enzymes that enable it to produce not only its normal fatty acids but also various branched-chain fatty acids with different chain lengths (C12-C16) and branch positions. The acyl transferase enzyme provides versatility by incorporating methylmalonyl-CoA at different positions in the fatty acid chain, allowing precise control over branch location while maintaining high productivity.
3Quantity of substance
If exogenous polynucleotides encoding propionyl-CoA carboxylase and methylmalonyl-CoA mutase are introduced, then branched-chain fatty acid production increases, but the cell complexity increases
Solution Approach 1:
The patent combines multiple functions into a coordinated system: propionyl-CoA carboxylase, methylmalonyl-CoA mutase, and acyl transferase work together in an integrated pathway. The enzymes are expressed from exogenous polynucleotides that are co-introduced into the cell, creating a unified metabolic pathway that produces branched-chain fatty acids efficiently without requiring separate complex systems for each function.
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 method significantly increases the production of branched-chain fatty acids with desired chain lengths and branch positions, enabling the production of commercially useful quantities and tailored fatty acid compositions.
Implementation Method 1
a polypeptide that catalyzes the conversion of propionyl-CoA to methylmalonyl-CoA... the polypeptide that catalyzes the conversion of propionyl-CoA to methylmalonyl-CoA is a propionyl-CoA carboxylase
Implementation Method 2
a polypeptide that catalyzes the conversion of succinyl-CoA to methylmalonyl-CoA... the polypeptide that catalyzes the conversion of succinyl-CoA to methylmalonyl-CoA is a methylmalonyl-CoA mutase
Implementation Method 3
Engineering Escherichia coli cells to overexpress specific polynucleotides encoding enzymes that convert propionyl-CoA to methylmalonyl-CoA and succinyl-CoA, allowing for the production of branched-chain fatty acids
Data Source
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AI summary
Methods and cells for producing scattered branched- chain fatty acids are provided. For example, the invention provides a method for producing branched- chain fatty acid comprising a methyl on one or more even number carbons. The method comprises culturing a cell comprising an exogenous or overexpressed polynucleotide comprising a nucleic acid sequence encoding a polypeptide that catalyzes the conversion of propionyl-CoA to methylmalonyl - CoA, such as propionyl - CoA carboxylase, and/or an exogenous or overexpressed polynucleotide comprising a nucleic acid sequence encoding a polypeptide that catalyzes the conversion of succinyl-CoA to methylmalonyl - CoA, such as methylmalonyl - CoA mutase, under conditions allowing expression of the polynucleotide (s) and production of branched- chain fatty acid. The cell produces more branched- chain fatty acid comprising a methyl on one or more even number carbons than an otherwise similar cell that does not comprise the polynucleotide (s). A cell that produces branched- chain fatty acid further comprising exogenous or overexpressed acyl transferase lacking polyketide synthetic activity and the branched- chain fatty acid also are provided.