Synthesis of medium-chain length (C6–C10) fuels and chemicals via β-oxidation reversal in Escherichia coli

Abstract

The recently engineered reversal of the β-oxidation cycle has been proposed as a potential platform for the efficient synthesis of longer chain (C ≥ 4) fuels and chemicals. Here, we demonstrate the utility of this platform for the synthesis of medium-chain length (C6-C10) products through the manipulation of key components of the pathway. Deletion of endogenous thioesterases provided a clean background in which the expression of various thiolase and termination components, along with required core enzymes, resulted in the ability to alter the chain length distribution and functionality of target products. This approach enabled the synthesis of medium-chain length carboxylic acids and primary alcohols from glycerol, a low-value feedstock. The use of BktB as the thiolase component with thioesterase TesA' as the termination enzyme enabled the synthesis of about 1.3 g/L C6-C10 saturated carboxylic acids. Tailoring of product formation to primary alcohol synthesis was achieved with the use of various acyl-CoA reductases. The combination of AtoB and FadA as the thiolase components with the alcohol-forming acyl-CoA reductase Maqu2507 from M. aquaeolei resulted in the synthesis of nearly 0.3 g/L C6-C10 alcohols. These results further demonstrate the versatile nature of a β-oxidation reversal, and highlight several key aspects and control points that can be further manipulated to fine-tune the synthesis of various fuels and chemicals.

Functional replacement of the Saccharomyces cerevisiae fatty acid synthase with a bacterial type II system allows flexible product profiles

“…chemical functionalities (Kim et al, 2015). In addition, the discrete type II FAS system allows expression to be optimized or even eliminated for each independent catalytic step.…”

Advances in bio‐based production of dicarboxylic acids longer than C4

“…For example, engineered strains of C. tropicalis by amplifying the copies of P450 genes and blocking β-oxidation either partially or completely produced up to 50 g/L C6 DCA, 140 g/L C12 DCA, 210 g/L C14 DCA or 100 g/L C18 DCA from fatty acids or alkanes [15,17]. 2A) [19,22]. Various P450 monoxygenases, oxidoreductases and esterases have been identified responsible for conversion of the terminal methyl to carboxyl group in carboxylic acids, and have been engineered with superior catalytic activity with an expanding substrate spectrum [18][19][20].…”

“…For example, an engineered pathway for the synthesis of medium chain carboxylic acids (C6-C10) was recently established ( Fig. 2A) [19,22]. In such pathway, expression of the alkBGT genes encoding an alkane monooxygenase system from Pseudomonas putida resulted in the production of ω-hydroxyacids.…”

Separation and detection of amino acid metabolites of Escherichia coli in microbial fuel cell with CE

“…Escherichia coli were widely used as the model organism to study their metabolism process in recent years . Some of the bacteria were genetic modified for biosynthesis purpose to produce lipids , alcohols , fatty acids , and so on. Amino acids, including some essential amino acids for human body, could be produced as metabolites by E. coli in their metabolism process .…”