Publications by authors named "Jungoh Ahn"

Indigo is a unique blue dye that has been used in the textile industry for centuries and is currently mass-produced commercially through chemical synthesis. However, the use of toxic substrates and reducing agents for chemical synthesis is associated with environmental concerns, necessitating the development of eco-friendly alternatives based on microbial production. In this study, a robust industrial strategy for indigo production was developed using Pseudomonas putida KT2440 as the host strain, which is characterized by its excellent ability to degrade aromatic compounds and high resistance to environmental stress.

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Article Synopsis
  • Researchers are tackling the low yield of polyhydroxyalkanoates (PHA) by exploring the use of δ-valerolactone (DVL) and plant oil to boost production without pre-treatment.
  • In their study, they found that PhaC enzyme effectively incorporated 5-hydroxyvalerate (5HV) into the PHA, resulting in significant biomass and synthesis during fed-batch fermentation.
  • The new PHAs showed improved properties, such as lower melting points and slower degradation rates, demonstrating potential benefits for polymer applications.
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Product inhibition caused by organic acids is a serious issue in establishing economical biochemical production systems. Herein, for enhanced production of glutaric acid by overcoming product inhibition triggered by glutaric acid, a whole-cell bioconversion system equipped with biocatalyst recycling process and in situ product recovery by adsorption was developed successfully. From the whole-cell bioconversion reaction, we found that both dissociated and undissociated forms of glutaric acid acted as an inhibitor in the whole-cell bioconversion reaction, wherein bioconversion was hindered beyond 200 mM glutaric acid regardless of reaction pH.

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Background: Palifermin (trade name Kepivance®) is an amino-terminally truncated recombinant human keratinocyte growth factor 1 (KGF-1) with 140 residues that has been produced using Escherichia coli to prevent and treat oral mucositis following radiation or chemotherapy. In this study, an amino-terminally shortened KGF-1 variant with 135 residues was produced and purified in E. coli, and its cell proliferation activity was evaluated.

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Petrochemical-based plastics are hardly biodegradable and a major cause of environmental pollution, and polyhydroxybutyrate (PHB) is attracting attention as an alternative due to its similar properties. However, the cost of PHB production is high and is considered the greatest challenge for its industrialization. Here, crude glycerol was used as a carbon source for more efficient PHB production.

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Indigo dye is an organic compound with a distinctive blue color. Most of the indigo currently used in industry is produced via chemical synthesis, which generates a large amount of wastewater. Therefore, several studies have recently been conducted to find ways to produce indigo eco-friendly using microorganisms.

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The α,ω-diamines (NH-(CH)-NH) and ω -amino fatty acids (NH-(CH)-COOH) have been widely used as building blocks in polymerindustries. Medium- to long-chain (C to C) fatty acid monomers with amino residues are almost exclusively produced chemical processes that generate hazardous waste and induce severe environmental problems, such as global warming and pollution. Here, we present the construction platformstrains of a cheese-ripening yeast, for direct biotransformation of hydrocarbons into medium- to long-chain α,ω-diamines and ωamino fatty acids using metabolic engineering of endogenous fatty acid ω- and β-oxidation pathways and introducing heterologous ω-transaminase in .

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Recombinant human keratinocyte growth factor 2 (KGF-2), also known as repifermin, is used in various therapeutic applications. However, KGF-2 production has not been optimized for facilitating large-scale production. Therefore, we attempted to attain high-level production of bioactive KGF-2.

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Using lignocellulosic biomass is immensely beneficial for the economical production of biochemicals. However, utilizing mixed sugars from lignocellulosic biomass is challenging because of bacterial preference for specific sugar such as glucose. Although previous studies have attempted to overcome this challenge, no studies have been reported on isobutanol production from mixed sugars in the Escherichia coli strain.

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As a biodegradable plastic, polyhydroxybutyrate (PHB) has relatively poor mechanical properties, preventing its wider use. Various plasticizers have been studied to improve the mechanical properties of PHB; however, due to the slow degradation speed in the soil environment and lack of evaluation methods, studies on the degradation of PHB with plasticizers are rarely reported. In this study, by applying sp.

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In the bioproduction of glutaric acid, an emerging bioplastic monomer, α-ketoglutaric acid (α-KG) is required as an amine acceptor for 4-aminobutyrate aminotransferase (GabT)-driven conversion of 5-aminovalerate (5-AVA) to glutarate semialdehyde. Herein, instead of using expensive α-KG, an indirect α-KG supply system was developed using a relatively cheap alternative, monosodium glutamate (MSG), for l-glutamate oxidase (Gox)-based whole-cell conversion. Using 200 mM 5-AVA and 30 mM MSG initially with Gox, 67.

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Gamma-aminobutyric acid (GABA) is a non-proteinogenic amino acid act as a major neurotransmitter inhibitor in the nervous system of mammals. It also used as a precursor of bioplastics synthesis such as N-methylpyrolidone and polyamide 4. Chemical-based synthesis methods have many environmental-related issues, so efforts have been made to develop biosynthetic methods to produce GABA.

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α,ω-Dodecanediol is a versatile material that has been widely used not only as an adhesive and crosslinking reagent, but also as a building block in the pharmaceutical and polymer industries. The biosynthesis of α,ω-dodecanediol from fatty derivatives, such as dodecane and dodecanol, requires an ω-specific hydroxylation step using monooxygenase enzymes. An issue with the whole-cell biotransformation of 1-dodecanol using cytochrome P450 monooxygenase (CYP) with ω-specific hydroxylation activity was the low conversion and production of the over-oxidized product of dodecanoic acid.

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Zingerone (vanillylacetone; 4-hydroxy-3-methoxyphenylethyl methyl ketone) is a key component responsible for the pungency of ginger (). In this study, it was confirmed that a type III polyketide synthase (PKS) gene () from exhibits feruloyl-CoA-preferred benzalacetone synthase (BAS) activity. Based on these results, we constructed an artificial biosynthetic pathway for zingerone production from supplemented ferulic acid with 4-coumarate CoA ligase (4CL), PmPKS, and benzalacetone reductase (BAR).

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A cDNA clone (named ), which shows high homology to the known chalcone synthase (CHS)-like type III PKS, was obtained from the leaves of . The PnPKS protein with ferulic acid catalyzed lactonization instead of chalcone or stilbene formation. The new product was characterized as a styrylpyrone, 11-methoxy-bisnoryangonin, which is the lactonization compound of a linear triketide formed as the reaction product of PnPKS protein with ferulic acid.

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Human enterokinase light chain (hEK) specifically cleaves the sequence (Asp)-Lys↓X (DK), making this a frequently used enzyme for site-specific cleavage of recombinant fusion proteins. However, hEK production from is limited due to intramolecular disulphide bonds. Here, we present strategies to obtain soluble and active hEK from by expressing the hEK variant C112S fused with maltose-binding protein (MBP) through DK and molecular chaperons including GroEL/ES.

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In the present study, an exopolysaccharide (EPS)-producing bacterial strain was isolated from the Eastern Sea (Sokcho Beach) of South Korea and identified as Sphingobium yanoikuyae BBL01. Media optimization was performed using response surface design, and a yield of 2.63 ± 0.

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Background: Growth factors (GFs) are signaling proteins that affect cellular processes such as growth, proliferation, and differentiation. GFs are used as cosmeceuticals, exerting anti-wrinkle, anti-aging, and whitening effects, and also as pharmaceuticals to treat wounds, growth failure, and oral mucositis. However, in mammalian and bacterial cells, low productivity and expression in inclusion bodies, respectively, of GFs does not satisfy the consumer demand.

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Aims: To genetically engineer the oleaginous yeast Yarrowia lipolytica for de novo production of tetraacetylphytosphingosine (TAPS), a precursor of phytosphingosine, and optimization of fermentation conditions for high yield.

Methods And Results: We successfully constructed a TAPS-producing Y. lipolytica CE3 strain by co-expression of Wickerhamomyces ciferrii-derived acetyl transferases, Sli1p and Atf2p.

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Once cells have been used to produce biochemicals, there are only a few effective ways to utilize the residual cell mass, even though the utilization of leftover cells would aid in decreasing production costs. Here, a polyhydroxybutyrate (PHB) and isobutanol co-production system was designed to address this challenge. The addition of the PHB operon into Escherichia coli conferred a metabolic advantage for alcohol production, generating 1.

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A new method has been developed for the preparation of brightly fluorescent and stable DNA-silver nanoclusters (DNA-AgNCs). The approach takes advantage of specific interactions occurring between melamine and thymine residues in a DNA template. These interactions cause the formation of a melamine-DNA-AgNC complex (Mel-DNA-AgNCs), in which a change in the environment of the DNA template causes binding of additional Ag and an enhancement in the fluorescence efficiency and stability.

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Volatile compounds can be produced by fermentation from genetically engineered microorganisms. Escherichia coli strains are mainly used for isoprene production owing to their higher titers; however, this has thus far been confined to only strains BL21, BL21 (DE3), Rosetta, and BW25113. Here, we tested four groups of E.

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Article Synopsis
  • Yarrowia lipolytica is a versatile yeast used in various industries, known for its ability to produce lipids and withstand stress.
  • The study aimed to enhance this yeast’s ploidy (number of chromosome sets) and evaluate a novel method for switching its mating types without interfering with genetics.
  • Researchers successfully converted mating-type genes and created a diploid strain that combines genetic traits from both parent cells, which can be applied for advanced engineering and increased productivity in industrial settings.
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Cytochrome P450s (CYPs) are heme-thiolated enzymes that catalyze the oxidation of CH bonds in a regio and stereoselective manner. Activation of the non-activated carbon atom can be further enhanced by multistep chemo-enzymatic reactions; moreover, several useful chemicals can be synthesized to provide alternative organic synthesis routes. Given their versatile functionality, CYPs show promise in a number of biotechnological fields.

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Glutaric acid is a C5 dicarboxylic acid that can be used as a building block for bioplastics. Although high concentrations of glutaric acid can be produced by fermentation or bioconversion, a large amount of α-ketoglutaric acid (α-KG) is necessary to accept the amine group from 5-aminovaleric acid. To decrease the demand for α-KG, we introduced l-glutamate oxidase (GOX) from Streptomyces mobaraensis in our previous system for cofactor regeneration in combination with a glutaric acid production system from 5-aminovaleric acid.

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