Biology subjects

Nieto-Dominguez, M.

Publications and source records attributed to Nieto-Dominguez, M..

2 recordsLinked to original sources

bioRxiv2024

Leveraging engineered Pseudomonas putida minicells for bioconversion of organic acids into short-chain methyl ketones

Methyl ketones, key building-blocks widely used in diverse industrial applications, largely depend on oil-derived chemical methods for their production. Here, we investigated bio-based production alternatives for short-chain ketones, adapting the solvent-tolerant soil bacterium Pseudomonas putida as a host for ketone biosynthesis either by whole-cell biocatalysis or using engineered minicells, chromosome-free bacterial vesicles. Organic acids (acetate, propanoate and butyrate) were selected as the main carbon substrate to drive the biosynthesis of acetone, 2-butanone and 2-pentanone. Pathway optimization identified efficient enzyme variants from Clostridium acetobutylicum and Escherichia coli, which were tested under both constitutive and inducible expression of the cognate genes. By implementing these optimized pathways in P. putida minicells, which can be prepared through a simple 3-step purification protocol, the feedstock was converted into the target short-chain methyl ketones, remaining catalytically functional for >4 months. These results highlight the value of combining morphology and pathway engineering of non-canonical bacterial hosts to establish alternative bioprocesses for toxic chemicals that are difficult to produce by conventional approaches. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=168 SRC="FIGDIR/small/574483v1_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@14db69eorg.highwire.dtl.DTLVardef@1104c0corg.highwire.dtl.DTLVardef@f0c725org.highwire.dtl.DTLVardef@1a28c2b_HPS_FORMAT_FIGEXP M_FIG C_FIG

synthetic biology↗

bioRxiv2023

High-yield enzymatic synthesis of mono- and trifluorinated alanine enantiomers

Fluorinated amino acids are a promising entry point for incorporating new-to-Nature chemistries in biological systems. Hence, novel methods are needed for the selective synthesis of these building blocks. In this study, we focused on the enzymatic synthesis of fluorinated alanine enantiomers. To this end, the alanine dehydrogenase from Vibrio proteolyticus and the diaminopimelate dehydrogenase from Symbiobacterium thermophilum were applied to the in vitro production of (R)-3-fluoroalanine and (S)-3-fluoroalanine, respectively, using 3-fluoropyruvate as the substrate. Additionally, an alanine racemase from Streptomyces lavendulae, originally selected for setting an alternative enzymatic cascade leading to the production of these non-canonical amino acids, had an unprecedented catalytic efficiency in the {beta}-elimination of fluorine from the monosubstituted fluoroalanine. The in vitro enzymatic cascade based on the dehydrogenases of V. proteolyticus and S. thermophilum included a cofactor recycling system, whereby a formate dehydrogenase from Pseudomonas sp. 101 (either native or engineered) coupled formate oxidation to NAD(P)H formation. Under these conditions, the reaction yields for (R)-3-fluoroalanine and (S)-3-fluoroalanine reached >85% on the fluorinated substrate and proceeded with complete enantiomeric excess. Moreover, the selected dehydrogenases were also able to catalyze the conversion of trifluoropyruvate into trifluorinated alanine, as a first-case example of biocatalysis with amino acids carrying a trifluoromethyl group.

synthetic biology↗