Soon Ho Hong

University of Ulsan, Urusan, Ulsan, South Korea

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Publications (45)100.42 Total impact

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    ABSTRACT: Zinc ion plays essential roles in biological chemistry. Bacteria acquire Zn(2+) from the environment, and cellular concentration levels are controlled by zinc homeostasis systems. In comparison with other homeostatic systems, the ZraSR two-component system was found to be more efficient in responding to exogenous zinc concentrations. To understand the dynamic response of the bacterium ZraSR two-component system with respect to exogenous zinc concentrations, the genetic circuit of the ZraSR system was integrated with a reporter protein. This study was helpful in the construction of an E. coli system that can display selective metal binding peptides on the surface of the cell in response to exogenous zinc. The engineered bacterial system for monitoring exogenous zinc was successfully employed to detect levels of zinc as low as 0.001 mM, which directly activates the expression of chimeric ompC(t)--zinc binding peptide gene to remove zinc by adsorbing a maximum of 163.6 μmol of zinc per gram of dry cell weight. These results indicate that the engineered bacterial strain developed in the present study can sense the specific heavy metal and activates a cell surface display system that acts to remove the metal.
    Bioprocess and Biosystems Engineering 06/2011; 34(9):1119-26. · 1.87 Impact Factor
  • European Journal of Medicinal Chemistry 01/2011; · 3.43 Impact Factor
  • PROCESS BIOCHEMISTRY 01/2011; · 2.41 Impact Factor
  • Biotechnology and Bioprocess Engineering 01/2011; · 1.28 Impact Factor
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    ABSTRACT: Methyl (R)-2-chloromandelate, a key intermediate in the synthesis of clopidogrel, was obtained by the reduction of methyl-2-chlorobenzoylformate using whole cells of Saccharomyces cerevisiae. A 100% conversion and 96.1% of enantiomeric excess (ee) value was obtained when 17 methyl-2-chlorobenzoylformate/l was reacted with 8 g S. cerevisiae/l and 83 g glucose/l at pH 7.
    Biotechnology Letters 10/2010; 32(10):1529-31. · 1.85 Impact Factor
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    ABSTRACT: A single submerged membrane bioreactor (MBR) for nitrification of ammonium and a pre-denitrification MBR process for total nitrogen (TN) removal were investigated in comparison. A single nitrifying MBR was fed with synthetic ammonium wastewater of up to 900mgN/l without organics so that the MBR was maintained as a pure nitrifying system. A high nitrifying capacity around 1.8kgNH4-N/m3/day was achieved while keeping the ammonium oxidation rate above 98%. Sludge volume index (SVI) gradually decreased down to less than 50 indicating good settleability of nitrifying sludge. The increase of suction pressure was less than 5cmHg over 7-months of operation. TN removal efficiency was determined in a pre-denitrification configuration with an anoxic reactor. Synthetic wastewater of 1200mgCOD/l and 200mgN/l was fed to the system at loads of 2.4kgCOD/m3/day and 0.4kgN/m3/day, respectively. As the internal recycle ratio from aerobic to anoxic zone increased from 2 to 6, TN removal efficiency was enhanced from 70±9 to 89±3%. With the sludge concentration of around 12,000mg/l, SVI was highly fluctuated from 60 to 350 indicating the partial deterioration of sludge settleability. The suction pressure after 8 months of operation increased to above 10cmHg which is higher than that in a single nitrifying MBR. The concentration of extracellular polymeric substances (EPS), especially for carbohydrate content, was higher in the operation of a pre-denitrification MBR process than in a single nitrifying MBR. It is likely that the sludge characteristic such as settleability is related with membrane fouling but, further extensive study is needed. The performance of a pre-denitrification MBR process was also verified with real petrochemical nitrogen wastewater.
    Journal of Industrial and Engineering Chemistry - J IND ENG CHEM. 01/2010; 16(4):546-550.
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    ABSTRACT: The evolution of living organisms occurs via a combination of highly complicated processes that involve modification of various features such as appearance, metabolism and sensing systems. To understand the evolution of life, it is necessary to understand how each biological feature has been optimized in response to new environmental conditions and interrelated with other features through evolution. To accomplish this, we constructed contents-based trees for two-component system (TCS) and metabolic network to determine how the environmental communication mechanism and the intracellular metabolism have evolved, respectively. We then conducted a comparative analysis of the two trees using ARACNE to evaluate the evolutionary and functional relationship between TCS and metabolism. The results showed that such integrated analysis can give new insight into the study of bacterial evolution.
    Journal of Microbiology and Biotechnology 11/2009; 19(11):1301-5. · 1.40 Impact Factor
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    ABSTRACT: A biosynthetic pathway for the production of (S)-3-hydroxybutyric acid (S3HB) from glucose was established in recombinant Escherichia coli by introducing the beta-ketothiolase gene from Ralstonia eutropha H16, the (S)-3-hydroxybutyryl-CoA dehydrogenase gene from R. eutropha H16, or Clostridium acetobutylicum ATCC824, and the 3-hydroxyisobutyryl-CoA hydrolase gene from Bacillus cereus ATCC14579. Artificial operon consisting of these genes was constructed and was expressed in E. coli BL21 (DE3) codon plus under T7 promoter by isopropyl beta-D: -thiogalactoside (IPTG) induction. Recombinant E. coli BL21 (DE3) codon plus expressing the beta-ketothiolase gene, the (S)-3-hydroxybutyryl-CoA dehydrogenase gene, and the 3-hydroxyisobutyryl-CoA hydrolase gene could synthesize enantiomerically pure S3HB to the concentration of 0.61 g l(-1) from 20 g l(-1) of glucose in Luria-Bertani medium. Fed-batch cultures of recombinant E. coli BL21 (DE3) codon plus were carried out to achieve higher titer of S3HB with varying induction time and glucose concentration during fermentation. Protein expression was induced by addition of 1 mM IPTG when cell concentration reached 10 and 20 g l(-1) (OD(600) = 30 and 60), respectively. When protein expression was induced at 60 of OD(600) and glucose was fed to the concentration of 15 g l(-1), 10.3 g l(-1) of S3HB was obtained in 38 h with the S3HB productivity of 0.21 g l(-1)h(-1). Lowering glucose concentration to 5 g l(-1) and induction of protein expression at 30 of OD(600) significantly reduced final S3HB concentration to 3.7 g l(-1), which also resulted in the decrease of the S3HB productivity to 0.05 g l(-1)h(-1).
    Applied Microbiology and Biotechnology 07/2008; 79(4):633-41. · 3.81 Impact Factor
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    ABSTRACT: Malic acid is a C4-dicarboxylic acid and an intermediate of tricarboxylic acid (TCA) cycle. It has been widely used in the polymer, food and pharmaceutical industries. Metabolic flux analysis was performed to find a strategy for enhanced malic acid production in Escherichia coli. The simulation results suggested that the amplification of phosphoenolpyruvate (PEP) carboxylation flux allowed increased malic acid production. Since the PEP carboxylase of E. coli converts PEP to oxaloacetate without generating ATP, thus losing the high-energy phosphate bond of PEP, the PEP carboxykinase, which generates ATP during this conversion, was chosen. However, the E. coli PEP carboxykinase catalyzes the reaction that converts oxaloacetate to PEP rather than the desirable opposite reaction. Thus, we cloned the PEP carboxykinase (enconded by the pckA gene) of Mannheimia succiniciproducens, which converts PEP to oxaloacetate as a favorable reaction. The pta mutant E. coli strain WGS-10 harboring the plasmid p104ManPck containing the M. succiniciproducens pckA gene was constructed and cultured at 37 °C. The final malic acid concentration of 9.25 g/L could be obtained after 12 h of aerobic cultivation.
    Biochemical Engineering Journal. 06/2008; 40(2):312–320.
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    ABSTRACT: ZnO thin films have been prepared by chemical bath deposition in aqueous/ethanolic solution. The film texture was successfully controlled by varying the volume ratio of water to ethanol. Films consisting of densely oriented nanorod arrays with the c-axis perpendicular to the substrate were fabricated in aqueous solution. The crystals became increasingly tilted as more ethanol was introduced to the solution, resulting in the cracked nanocolumns and the smoothed crystals. The crystal size was decreased with increasing ethanol content, and granular morphology was obtained in films deposited in ethanolic solution. A gradual evolution of the film texture is possibly due to the inhibited crystal growth in solution with higher ethanol content.
    Materials Letters - MATER LETT. 01/2008; 62(30):4532-4534.
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    Soon Ho Hong
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    ABSTRACT: Succinic acid is a cellular metabolite belonging to the C4-dicarboxylic acid family, and the fermentative production of succinic acid via the use of recombinant microorganisms has recently become the focus of an increasing amount of attention. Considering the difficulty inherent to the direct application of natural succinic acid producers to the industrial process, a variety of systems biology studies have been conducted regarding the development of enhanced succinic acid production systems. This review shows how the metabolic processes of microorganisms, includingEscherichia coli andMannheimia succiniciproducens, have been optimized in order to achieve enhanced succinic acid production. First, their metabolic networks were constructed on the basis of complete genome sequences, after which their metabolic characteristics were estimated viain silico computer modeling. Metabolic engineering strategies were designed in accordance with the results ofin silico modeling and metabolically engineered versions of bothE. coli andM. succiniciproducens have been constructed. The succinic acid productivity and yield obtained using metabolically engineered bacteria was significantly higher than that obtained using wild-type bacteria.
    Biotechnology and Bioprocess Engineering 01/2007; 12(2):73-79. · 1.28 Impact Factor
  • Biopolymers Online, 01/2005; , ISBN: 9783527600038
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    ABSTRACT: The rumen represents the first section of a ruminant animal's stomach, where feed is collected and mixed with microorganisms for initial digestion. The major gas produced in the rumen is CO(2) (65.5 mol%), yet the metabolic characteristics of capnophilic (CO(2)-loving) microorganisms are not well understood. Here we report the 2,314,078 base pair genome sequence of Mannheimia succiniciproducens MBEL55E, a recently isolated capnophilic Gram-negative bacterium from bovine rumen, and analyze its genome contents and metabolic characteristics. The metabolism of M. succiniciproducens was found to be well adapted to the oxygen-free rumen by using fumarate as a major electron acceptor. Genome-scale metabolic flux analysis indicated that CO(2) is important for the carboxylation of phosphoenolpyruvate to oxaloacetate, which is converted to succinic acid by the reductive tricarboxylic acid cycle and menaquinone systems. This characteristic metabolism allows highly efficient production of succinic acid, an important four-carbon industrial chemical.
    Nature Biotechnology 11/2004; 22(10):1275-81. · 32.44 Impact Factor
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    ABSTRACT: We have developed MetaFluxNet which is a stand-alone program package for the management of metabolic reaction information and quantitative metabolic flux analysis. It allows users to interpret and examine metabolic behavior in response to genetic and/or environmental modifications.
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    Soon Ho Hong, Sang Yup Lee
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    ABSTRACT: Apfl ldhA double mutantEscherichia coli strain NZN111 was used to produce succinic acid by overexpressing theE. coli malic enzyme gene (sfcA). This strain, however, produced a large amount of malic acid as well as succinic acid. After the analyses of the metabolic pathways, thefumB gene encoding the anaerobic fumarase ofE. coli was co-amplified to solve the problem of malic acid accumulation. A plasmid, pTrcMLFu, was constructed, which contains an artificial operon (sfcA-fumB) under the control of the inducibletrc promoter. From the batch culture of recombinantE. coli NZN111 harboring pTrcMLFu, 7 g/L of succinic acid was produced from 20 g/L of glucose, with no accumulation of malic acid. From the metabolic flux analysis the strain was found under reducing power limiting conditions by severe reorientation of metabolic fluxes.
    Biotechnology and Bioprocess Engineering 01/2004; 9(4):252-255. · 1.28 Impact Factor
  • 01/2004;
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    ABSTRACT: The metabolic network of Escherichia coli was constructed and was used to simulate the distribution of metabolic fluxes in wild-type E. coli and recombinant E. coli producing poly(3-hydroxybutyrate) [P(3HB)]. The flux of acetyl-CoA into the tricarboxylic acid (TCA) cycle, which competes with the P(3HB) biosynthesis pathway, decreased significantly during P(3HB) production. It was notable to find from in silico analysis that the Entner-Doudoroff (ED) pathway flux increased significantly under P(3HB)-accumulating conditions. To prove the role of ED pathway on P(3HB) production, a mutant E. coli strain, KEDA, which is defective in the activity of 2-keto-3-deoxy-6-phosphogluconate aldolase (Eda), was examined as a host strain for the production of P(3HB) by transforming it with pJC4, a plasmid containing the Alcaligenes latus P(3HB) biosynthesis operon. The P(3HB) content obtained with KEDA (pJC4) was lower than that obtained with its parent strain KS272 (pJC4). The reduced P(3HB) biosynthetic capacity of KEDA (pJC4) could be restored by the co-expression of the E. coli eda gene, which proves the important role of ED pathway on P(3HB) synthesis in recombinant E. coli as predicted by metabolic flux analysis.
    Biotechnology and Bioengineering 10/2003; 83(7):854-63. · 4.16 Impact Factor
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    ABSTRACT: We have developed MetaFluxNet which is a stand-alone program package for the management of metabolic reaction information and quantitative metabolic flux analysis. It allows users to interpret and examine metabolic behavior in response to genetic and/or environmental modifications. As a result, quantitative in silico simulations of metabolic pathways can be carried out to understand the metabolic status and to design the metabolic engineering strategies. The main features of the program include a well-developed model construction environment, user-friendly interface for metabolic flux analysis (MFA), comparative MFA of strains having different genotypes under various environmental conditions, and automated pathway layout creation. The usefulness and functionality of the program are demonstrated by applying to metabolic pathways in E. coli. First, a large-scale in silico E. coli model is constructed using MetaFluxNet, and then the effects of carbon sources on intracellular flux distributions and succinic acid production were investigated on the basis of the uptake and secretion rates of the relevant metabolites. The results indicated that among three carbon sources available, the most reduced substrate is sorbitol which yields efficient succinic acid production. The software can be downloaded from
    Genome informatics. International Conference on Genome Informatics 02/2003; 14:23-33.
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    Sang Yup Lee, Soon Ho Hong, Soo Yun Moon
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    ABSTRACT: The intracellular metabolic fluxes can be calculated by metabolic flux analysis, which uses a stoichiometric model for the intracellular reactions along with mass balances around the intracellular metabolites. In this study, we have constructed in silico metabolic pathway network of Escherichia coli consisting of 301 reactions and 294 metabolites. Metabolic flux analyses were carried out to estimate flux distributions to achieve the maximum in silico yield of succinic acid in E. coli. The maximum in silico yield of succinic acid was only 83% of its theoretical yield. The lower in silico yield of succinic acid was found to be due to the insufficient reducing power, which could be increased to its theoretical yield by supplying more reducing power. Furthermore, the optimal metabolic pathways for the production of succinic acid could be proposed based on the results of metabolic flux analyses. In the case of succinic acid production, it was found that pyruvate carboxylation pathway should be used rather than phosphoenolpyruvate carboxylation pathway for its optimal production in E. coli. Then, the in silico optimal succinic acid pathway was compared with conventional succinic acid pathway through minimum set of wet experiments. The results of wet experiments indicate that the pathway predicted by in silico analysis is more efficient than conventional pathway.
    Genome informatics. International Conference on Genome Informatics 01/2002; 13:214-23.
  • Soon Ho Hong, Sang Yup Lee
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    ABSTRACT: A pfl ldhA double mutant Escherichia coli strain NZN111 was used to produce succinic acid by overexpressing the E. coli malic enzyme. Escherichia coli strain NZN111 harboring pTrcML produced 6 and 8 g/L of succinic acid from 20 g/L of glucose in flask culture at 37°C and 30°C, respectively. When NZN111(pTrcML) was cultured at 30°C with intermittent glucose feeding the final succinic acid concentration obtained was 9.5 g/L and the ratio of succinic acid to acetic acid was 13:1. This system could not be analyzed by conventional metabolic flux analysis techniques, since some pyruvate and succinic acid were accumulated intracellularly. Therefore, a new flux analysis method was proposed by introducing intracellular pyruvate and succinic acid pools. By this new method the concentrations of intracellular metabolites were successfully predicted and the differences between the measured and calculated reaction rates could be considerably reduced. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 74: 89–95, 2001.
    Biotechnology and Bioengineering 07/2001; 74(2):89 - 95. · 4.16 Impact Factor

Publication Stats

349 Citations
100.42 Total Impact Points


  • 2007–2014
    • University of Ulsan
      • • Department of Chemical Engineering
      • • School of Chemical Engineering and Bioengineering
      Urusan, Ulsan, South Korea
  • 2013
    • Korea Research Institute of Chemical Technology
      • Division of Drug Discovery Research
      Daiden, Daejeon, South Korea
  • 2012
    • Dongyang University
      South Korea
  • 2001–2004
    • Korea Advanced Institute of Science and Technology
      • • Department of Chemical and Biomolecular Engineering
      • • Metabolic and Biomolecular Engineering National Research Laboratory
      Seoul, Seoul, South Korea