ChemInform Abstract: Dehydroacetic Acid, Triacetic Acid Lactone, and Related Pyrones

ChemInform ◽  
2010 ◽  
Vol 24 (9) ◽  
pp. no-no
Author(s):  
M. MORENO-MANAS ◽  
R. PLEIXATS
Keyword(s):  
Dehydroacetic Acid ◽  
Acid Lactone ◽  
Triacetic Acid Lactone

scholarly journals Engineering sensitivity and specificity of AraC-based biosensors responsive to triacetic acid lactone and orsellinic acid

2020 ◽  
Vol 33 ◽  
Author(s):  
Zhiqing Wang ◽  
Aarti Doshi ◽  
Ratul Chowdhury ◽  
Yixi Wang ◽  
Costas D Maranas ◽  
...  
Keyword(s):  
Directed Evolution ◽  
Negative Selection ◽  
Regulatory Protein ◽  
Polyketide Synthases ◽  
Computational Framework ◽  
Orsellinic Acid ◽  
Acid Lactone ◽  
Triacetic Acid Lactone ◽  
Protein Redesign ◽  
Background Expression

Abstract We previously described the design of triacetic acid lactone (TAL) biosensor ‘AraC-TAL1’, based on the AraC regulatory protein. Although useful as a tool to screen for enhanced TAL biosynthesis, this variant shows elevated background (leaky) expression, poor sensitivity and relaxed inducer specificity, including responsiveness to orsellinic acid (OA). More sensitive biosensors specific to either TAL or OA can aid in the study and engineering of polyketide synthases that produce these and similar compounds. In this work, we employed a TetA-based dual-selection to isolate new TAL-responsive AraC variants showing reduced background expression and improved TAL sensitivity. To improve TAL specificity, OA was included as a ‘decoy’ ligand during negative selection, resulting in the isolation of a TAL biosensor that is inhibited by OA. Finally, to engineer OA-specific AraC variants, the iterative protein redesign and optimization computational framework was employed, followed by 2 rounds of directed evolution, resulting in a biosensor with 24-fold improved OA/TAL specificity, relative to AraC-TAL1.

scholarly journals Rewiring Yarrowia lipolytica toward triacetic acid lactone for materials generation

2018 ◽  
Vol 115 (9) ◽  
pp. 2096-2101 ◽  
Author(s):  
Kelly A. Markham ◽  
Claire M. Palmer ◽  
Malgorzata Chwatko ◽  
James M. Wagner ◽  
Clare Murray ◽  
...  
Keyword(s):  
Yarrowia Lipolytica ◽  
Building Blocks ◽  
Specific Productivity ◽  
Chemical Production ◽  
Conversion Yield ◽  
Acetyl Coa ◽  
Type Iii Polyketide Synthase ◽  
Chemical Catalysis ◽  
Acid Lactone ◽  
Triacetic Acid Lactone

Polyketides represent an extremely diverse class of secondary metabolites often explored for their bioactive traits. These molecules are also attractive building blocks for chemical catalysis and polymerization. However, the use of polyketides in larger scale chemistry applications is stymied by limited titers and yields from both microbial and chemical production. Here, we demonstrate that an oleaginous organism (specifically, Yarrowia lipolytica) can overcome such production limitations owing to a natural propensity for high flux through acetyl–CoA. By exploring three distinct metabolic engineering strategies for acetyl–CoA precursor formation, we demonstrate that a previously uncharacterized pyruvate bypass pathway supports increased production of the polyketide triacetic acid lactone (TAL). Ultimately, we establish a strain capable of producing over 35% of the theoretical conversion yield to TAL in an unoptimized tube culture. This strain also obtained an averaged maximum titer of 35.9 ± 3.9 g/L with an achieved maximum specific productivity of 0.21 ± 0.03 g/L/h in bioreactor fermentation. Additionally, we illustrate that a β-oxidation-related overexpression (PEX10) can support high TAL production and is capable of achieving over 43% of the theoretical conversion yield under nitrogen starvation in a test tube. Next, through use of this bioproduct, we demonstrate the utility of polyketides like TAL to modify commodity materials such as poly(epichlorohydrin), resulting in an increased molecular weight and shift in glass transition temperature. Collectively, these findings establish an engineering strategy enabling unprecedented production from a type III polyketide synthase as well as establish a route through O-functionalization for converting polyketides into new materials.

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