Chimeric Alcohol Acyltransferases for Ester Biosynthesis
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Solution Overview
Problem
Current methods for microbial biosynthesis of designer esters face challenges such as limited robustness and efficiency of alcohol acyltransferases (AATs), substrate promiscuity, and poor selectivity, which hinder high-yield production of specific esters.
Innovation Solution
A high-throughput microbial screening platform using in situ fermentation with a solvent overlay and a colorimetric microplate assay is developed to identify and quantify AATs for ester biosynthesis. This platform involves preselected plasmids, engineered microbes, and a modular design of ester biosynthesis pathways to enhance production efficiency and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If eukaryotic AATs are used for microbial biosynthesis of esters, then the enzymes can catalyze ester formation, but they exhibit poor expression, solubility, and thermostability in microbes
Solution Approach 1:
The patent segments the AAT enzyme into modular components and combines them with microbial enzymes to create chimeric proteins that retain catalytic activity while gaining microbial compatibility and stability
Solution Approach 2:
The patent creates composite enzyme systems by fusing eukaryotic AAT domains with microbial protein structures, resulting in hybrid enzymes that exhibit both the catalytic specificity of eukaryotic AATs and the stability/expression properties of microbial enzymes
2Adaptability or versatility
If substrate promiscuous AATs are used, then various esters can be produced, but selectivity for specific designer esters is poor
Solution Approach 1:
The patent modifies specific local regions of the AAT enzyme structure to alter substrate binding pockets, enabling the enzyme to maintain broad substrate acceptance while showing enhanced preference for specific alcohol or acyl-CoA substrates
Solution Approach 2:
The patent changes key parameters of enzyme-substrate interaction through mutagenesis, adjusting binding affinity and catalytic efficiency to achieve desired selectivity for target esters while preserving versatility
3Measurement precision
If traditional screening methods are used for AAT identification, then enzyme activity can be assessed, but the process is laborious and time-consuming
Solution Approach 1:
The patent employs colorimetric assays where enzyme activity produces detectable color changes in the culture medium, enabling rapid visual or spectrophotometric screening of numerous AAT candidates simultaneously
Solution Approach 2:
The patent creates and screens libraries of AAT variant copies using high-throughput molecular biology techniques, allowing parallel assessment of many enzymes and rapid identification of optimal candidates
4Manufacturing precision
If laborious bioprospecting is performed for individual target esters, then AAT specificity can be determined, but the process requires extensive resources
Solution Approach 1:
The patent develops universal screening platforms and reporter systems that can assess AAT activity and specificity for multiple different target esters using the same experimental framework, eliminating the need for separate bioprospecting campaigns for each ester
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 enables rapid and efficient identification of AATs with improved specificity and activity, leading to higher yields and selectivity in microbial biosynthesis of designer esters, such as butyryl-coenzyme A (CoA) derived esters.
Implementation Method 1
an alcohol acyltransferase (AAT, EC 2.3.1.84) that condenses an alcohol and an acyl-CoA in a thermodynamically favorable reaction
Implementation Method 2
a colorimetric microplate assay of the solvent overlay for ester concentration
Implementation Method 3
in situ fermentation with a solvent overlay
Data Source
AI summary
Methods of microbial screening for identifying alcohol acyltransferases for ester biosynthesis and submodules for ester pathways to produce butyryl-coenzyme A derived esters are disclosed. The method includes the introduction preselected plasmids into a respective host strain to form engineered microbes, in situ fermentation thereof followed by a colorimetric assay for quantification of production of the target ester. In situ fermentation includes inoculating each well of a microplate that have a culture media for producing target esters with one of the engineered microbes, adding an overlay of a solvent to each, and incubating the same. The colorimetric assay includes transfer of a quantity of the overlay from each well to respective clean wells of a new microplate, treatment of each well to form an iron-hydroxamic acid complex aqueous phase, centrifugation of the microplate, and measurement of the absorbance at 520 nm and comparison to a standard curve for the target ester.