Microbial Biocatalyst for 1,4-Butanediol Biosynthesis
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Solution Overview
Problem
Current methods for producing 1,4-butanediol and its precursors are energy- and capital-intensive, relying on petroleum-based feedstocks, and alternative biologically-produced intermediates like succinic acid are costly and require high temperatures and pressures.
Innovation Solution
Development of non-naturally occurring microbial biocatalysts with engineered 4-hydroxybutanoic acid and 1,4-butanediol biosynthetic pathways, using exogenous nucleic acids encoding specific enzymes, to produce these chemicals under anaerobic conditions, allowing for efficient biosynthesis and secretion of 4-HB and BDO.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional petrochemical methods are used to produce 1,4-butanediol, then production efficiency is high, but energy consumption and capital requirements are excessive
Solution Approach 1:
The patent replaces mechanical/chemical catalytic systems with biological enzymatic systems. Microorganisms equipped with specific enzyme pathways (4-hydroxybutanoate dehydrogenase, succinyl-CoA synthetase, CoA-dependent succinic semialdehyde dehydrogenase, and α-ketoglutarate decarboxylase) perform the chemical transformations that traditionally required high-temperature catalytic hydrogenation, thereby reducing energy consumption while maintaining productivity
Solution Approach 2:
The patent fundamentally changes the operating parameters from high-temperature and high-pressure conditions to ambient temperature and pressure conditions. The biosynthetic pathway operates under physiological conditions (pH 6.0-8.0, temperature 20-40°C), eliminating the need for energy-intensive high-temperature catalytic reduction while achieving comparable production rates
2Adaptability or versatility
If succinic acid is used as a biologically-produced intermediate, then renewable feedstocks are utilized, but isolation and purification costs are high and processing requires high temperatures and pressures
Solution Approach 1:
The patent extracts and utilizes only the essential enzymatic steps from the complete succinic acid biosynthetic pathway. By implementing a truncated pathway that produces 4-hydroxybutanoic acid directly from α-ketoglutarate or succinyl-CoA (bypassing the need for complete succinic acid formation), the invention eliminates the costly isolation and purification steps associated with producing full succinic acid while still achieving the desired product
Solution Approach 2:
The patent introduces 4-hydroxybutanoic acid as an intermediary compound that bridges renewable feedstock utilization and final product formation. This intermediate can be directly converted to 1,4-butanediol under mild conditions, serving as a more convenient alternative to succinic acid and eliminating the need for high-temperature catalytic reduction
3Productivity
If conventional catalytic reduction methods are used, then butanediol production is achieved, but high temperatures and pressures are required
Solution Approach 1:
The patent substitutes thermal catalytic reduction with enzymatic reduction. The expressed enzymes (particularly alcohol dehydrogenase and aldehyde dehydrogenase) catalyze the conversion of 4-hydroxybutanoic acid to 1,4-butanediol at temperatures between 20-40°C, replacing the conventional high-temperature (150-300°C) catalytic hydrogenation process while maintaining high productivity through efficient enzymatic catalysis
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 the production of 4-HB and BDO with reduced energy and capital requirements, avoiding the high costs and pressures associated with traditional methods, and allows for the spontaneous conversion of 4-HB to γ-butyrolactone, facilitating the biosynthesis of downstream products like 1,4-butanediol and tetrahydrofuran.
Implementation Method 1
a microbial organism having a 4-hydroxybutanoic acid (4-HB) biosynthetic pathway having at least one exogenous nucleic acid encoding 4-hydroxybutanoate dehydrogenase, succinyl-CoA synthetase, CoA-dependent succinic semialdehyde dehydrogenase, or α-ketoglutarate decarboxylase
Implementation Method 2
The method includes culturing a non-naturally occurring microbial organism having a 4-hydroxybutanoic acid (4-HB) biosynthetic pathway under substantially anaerobic conditions for a sufficient period of time to produce monomeric 4-hydroxybutanoic acid (4-HB)
Data Source
AI summary
The invention provides a non-naturally occurring microbial biocatalyst including a microbial organism having a 4-hydroxybutanoic acid (4-HB) biosynthetic pathway having at least one exogenous nucleic acid encoding 4-hydroxybutanoate dehydrogenase, succinyl-CoA synthetase, CoA-dependent succinic semialdehyde dehydrogenase, or α-ketoglutarate decarboxylase, wherein the exogenous nucleic acid is expressed in sufficient amounts to produce monomeric 4-hydroxybutanoic acid (4-HB). Also provided is a non-naturally occurring microbial biocatalyst including a microbial organism having 4-hydroxybutanoic acid (4-HB) and 1,4-butanediol (BDO) biosynthetic pathways, the pathways include at least one exogenous nucleic acid encoding 4-hydroxybutanoate dehydrogenase, succinyl-CoA synthetase, CoA-dependent succinic semialdehyde dehydrogenase, 4-hydroxybutyrate:CoA transferase, 4-butyrate kinase, phosphotransbutyrylase, α-ketoglutarate decarboxylase, aldehyde dehydrogenase, alcohol dehydrogenase or an aldehyde/alcohol dehydrogenase, wherein the exogenous nucleic acid is expressed in sufficient amounts to produce 1,4-butanediol (BDO). Additionally provided are methods for the production of 4-HB and BDO.