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Now showing items 1 - 16 of 73

  • Microbial production of methyl anthranilate, a grape flavor compound

    Luo, Zi Wei   Cho, Jae Sung   Lee, Sang Yup  

    Methyl anthranilate (MANT) is a widely used compound to give grape scent and flavor, but is currently produced by petroleum-based processes. Here, we report the direct fermentative production of MANT from glucose by metabolically engineered Escherichia coli and Corynebacterium glutamicum strains harboring a synthetic plantderived metabolic pathway. Optimizing the key enzyme anthranilic acid (ANT) methyltransferasel (AAMT1) expression, increasing the direct precursor ANT supply, and enhancing the intracellular availability and salvage of the cofactor S-adenosyl-L-methionine required by AAMT1, results in improved MANT production in both engineered microorganisms. Furthermore, in situ two-phase extractive fermentation using tributyrin as an extractant is developed to overcome MANT toxicity. Fed-batch cultures of the final engineered E. coli and C glutamicum strains in two-phase cultivation mode led to the production of 4.47 and 5.74 g/L MANT, respectively, in minimal media containing glucose. The metabolic engineering strategies developed here will be useful for the production of volatile aromatic esters including MANT.
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  • A comprehensive metabolic map for production of bio-based chemicals

    Lee, Sang Yup   Kim, Hyun Uk   Chae, Tong Un   Cho, Jae Sung   Kim, Je Woong   Shin, Jae Ho   Kim, Dong In   Ko, Yoo-Sung   Jang, Woo Dae   Jang, Yu-Sin  

    Production of industrial chemicals using renewable biomass feedstock is becoming increasingly important to address limited fossil resources, climate change and other environmental problems. To develop high-performance microbial cell factories, equivalent to chemical plants, microorganisms undergo systematic metabolic engineering to efficiently convert biomass-derived carbon sources into target chemicals. Over the past two decades, many engineered microorganisms capable of producing natural and non-natural chemicals have been developed. This Review details the current status of representative industrial chemicals that are produced through biological and/or chemical reactions. We present a comprehensive bio-based chemicals map that highlights the strategies and pathways of single or multiple biological reactions, chemical reactions and combinations thereof towards production of particular chemicals of interest. Future challenges are also discussed to enable production of even more diverse chemicals and more efficient production of chemicals from renewable feedstocks.
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  • A comprehensive metabolic map for production of bio-based chemicals

    Lee, Sang Yup   Kim, Hyun Uk   Chae, Tong Un   Cho, Jae Sung   Kim, Je Woong   Shin, Jae Ho   Kim, Dong In   Ko, Yoo-Sung   Jang, Woo Dae   Jang, Yu-Sin  

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  • WALKING ANALYSIS SYSTEM AND METHOD, AND COMPUTER-READABLE RECORDING MEDIUM

    A walking analysis system and method, and a computer-readable recording medium are disclosed. According to one embodiment of the present invention, the walking analysis method comprises the steps of: measuring lower limb joint angles of a walker through an inertial measurement device attached to the walker's body; extracting a walking event by using gyroscope data acquired through the inertial measurement device; detecting walking steps from the walking event, and subdividing the joint angles for each walking step; performing machine learning for the joint angles subdivided for each walking step, so as to classify the same into a plurality groups according to data characteristics; and determining the severity of a knee joint disease for the plurality of groups.
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  • Virtual Reality Training Improves da Vinci Performance: A Prospective Trial

    Cho, Jae Sung   Hahn, Koo Yong   Kwak, Jung Myun   Kim, Jin   Baek, Se Jin   Shin, Jae Won   Kim, Seon Hahn  

    Introduction: The DV-Trainer (TM) (a virtual reality [VR] simulator) (Mimic Technologies, Inc., Seattle, WA) is one of several different robotic surgical training methods. We designed a prospective study to determine whether VR training could improve da Vinci (R) Surgical System (Intuitive Surgical, Inc., Sunnyvale, CA) performance. Subjects and Methods: Surgeons (n = 12) were enrolled using a randomized protocol. Groups 1 (VR training) and 2 (control) participated in VR and da Vinci exercises. Participants' time and moving distance were combined to determine a composite score: VR index = 1000/(time u moving distance). The da Vinci exercises included needle control and suturing. Procedure time and error were measured. A composite index (DV index) was computed and used to measure da Vinci competency. After the initial trial with both the VR and da Vinci exercises, only Group 1 was trained with the VR simulator following our institutional curriculum for 3 weeks. All members of both groups then participated in the second trial of the VR and da Vinci exercises and were scored in the same way as in the initial trial. Results: In the initial trial, there was no difference in the VR index (Group 1 versus Group 2, 8.9 +/- 3.3 versus 9.4 +/- 3.7; P =.832) and the DV index (Group 1 versus Group 2, 3.85 +/- 0.73 versus 3.66 +/- 0.65; P =.584) scores between the two groups. At the second time point, Group 1 showed increased VR index scores in comparison with Group 2 (19.3 +/- 4.5 versus 9.7 +/- 4.1, respectively; P =.001) and improved da Vinci performance skills as measured by the DV index (5.80 +/- 1.13 versus 4.05 +/- 1.03, respectively; P =.028) and by suturing time (7.1 +/- 1.54 minutes versus 10.55 +/- 1.93 minutes, respectively; P =.018). Conclusions: We found that VR simulator training can improve da Vinci performance. VR practice can result in an early plateau in the learning curve for robotic practice under controlled circumstances.
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  • A comprehensive metabolic map for production of bio-based chemicals (vol 2,pg 18,2019)

    Lee, Sang Yup   Kim, Hyun Uk   Chae, Tong Un   Cho, Jae Sung   Kim, Je Woong   Shin, Jae Ho   Kim, Dong In   Ko, Yoo-Sung   Jang, Woo Dae   Jang, Yu-Sin  

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  • CRISPR/Cas9-coupled recombineering for metabolic engineering of Corynebacterium glutamicum

    Cho, Jae Sung   Choi, Kyeong Rok   Prabowo, Cindy Pricilia Surya   Shin, Jae Ho   Yang, Dongsoo   Jang, Jaedong   Lee, Sang Yup  

    Genome engineering of Corynebacterium glutamicum, an important industrial microorganism for amino acids production, currently relies on random mutagenesis and inefficient double crossover events. Here we report a rapid genome engineering strategy to scarlessly knock out one or more genes in C. glutamicum in sequential and iterative manner. Recombinase RecT is used to incorporate synthetic single-stranded oligodeoxyribonucleotides into the genome and CRISPR/Cas9 to counter-select negative mutants. We completed the system by engineering the respective plasmids harboring CRISPR/Cas9 and RecT for efficient curing such that multiple gene targets can be done iteratively and final strains will be free of plasmids. To demonstrate the system, seven different mutants were constructed within two weeks to study the combinatorial deletion effects of three different genes on the production of.-aminobutyric acid, an industrially relevant chemical of much interest. This genome engineering strategy will expedite metabolic engineering of C. glutamicum.
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  • CRISPR/Cas9-coupled recombineering for metabolic engineering of Corynebacterium glutamicum

    Cho, Jae Sung   Choi, Kyeong Rok   Prabowo, Cindy Pricilia Surya   Shin, Jae Ho   Yang, Dongsoo   Jang, Jaedong   Lee, Sang Yup  

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  • Metabolic engineering of Corynebacterium glutamicum for enhanced production of 5-aminovaleric acid

    Shin, Jae Ho   Park, Seok Hyun   Oh, Young Hoon   Choi, Jae Woong   Lee, Moon Hee   Cho, Jae Sung   Jeong, Ki Jun   Joo, Jeong Chan   Yu, James  

    Background: 5-Aminovaleric acid (5AVA) is an important five-carbon platform chemical that can be used for the synthesis of polymers and other chemicals of industrial interest. Enzymatic conversion of l-lysine to 5AVA has been achieved by employing lysine 2-monooxygenase encoded by the davB gene and 5-aminovaleramidase encoded by the davA gene. Additionally, a recombinant Escherichia coli strain expressing the davB and davA genes has been developed for bioconversion of l-lysine to 5AVA. To use glucose and xylose derived from lignocellulosic biomass as substrates, rather than l-lysine as a substrate, we previously examined direct fermentative production of 5AVA from glucose by metabolically engineered E. coli strains. However, the yield and productivity of 5AVA achieved by recombinant E. coli strains remain very low. Thus, Corynebacterium glutamicum, a highly efficient l-lysine producing microorganism, should be useful in the development of direct fermentative production of 5AVA using l-lysine as a precursor for 5AVA. Here, we report the development of metabolically engineered C. glutamicum strains for enhanced fermentative production of 5AVA from glucose.Results: Various expression vectors containing different promoters and origins of replication were examined for optimal expression of Pseudomonas putida davB and davA genes encoding lysine 2-monooxygenase and delta-aminovaleramidase, respectively. Among them, expression of the C. glutamicum codon-optimized davA gene fused with His(6)-Tag at its N-Terminal and the davB gene as an operon under a strong synthetic H-36 promoter (plasmid p36davAB3) in C. glutamicum enabled the most efficient production of 5AVA. Flask culture and fed-batch culture of this strain produced 6.9 and 19.7 g/L (together with 11.9 g/L glutaric acid as major byproduct) of 5AVA, respectively. Homology modeling suggested that endogenous gamma-aminobutyrate aminotransferase encoded by the gabT gene might be responsible for the conversion of 5AVA to glutaric acid in recombinant C. glutamicum. Fed-batch culture of a C. glutamicum gabT mutant-harboring p36davAB3 produced 33.1 g/L 5AVA with much reduced (2.0 g/L) production of glutaric acid.Conclusions: Corynebacterium glutamicum was successfully engineered to produce 5AVA from glucose by optimizing the expression of two key enzymes, lysine 2-monooxygenase and delta-aminovaleramidase. In addition, production of glutaric acid, a major byproduct, was significantly reduced by employing C. glutamicum gabT mutant as a host strain. The metabolically engineered C. glutamicum strains developed in this study should be useful for enhanced fermentative production of the novel C5 platform chemical 5AVA from renewable resources.
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  • Systems metabolic engineering as an enabling technology in accomplishing sustainable development goals

    Yang, Dongsoo   Cho, Jae Sung   Choi, Kyeong Rok   Kim, Hyun Uk   Lee, Sang Yup  

    With pressing issues arising in recent years, the United Nations proposed 17 Sustainable Development Goals (SDGs) as an agenda urging international cooperations for sustainable development. In this perspective, we examine the roles of systems metabolic engineering (SysME) and its contribution to improving the quality of life and protecting our environment, presenting how this field of study offers resolutions to the SDGs with relevant examples. We conclude with offering our opinion on the current state of SysME and the direction it should move forward in the generations to come, explicitly focusing on addressing the SDGs.
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  • Idiopathic Fibrosing Mediastinitis Causing Pulmonary Hypertension with Improvement by Steroid Treatment

    Jung, Bo Yong   Eo, Sung Jun   Park, Eun Seo   Kim, Young Tong   Cho, Jae Sung   Oh, Mi Hye   Seo, Gi Hyun   Na, Joo Ock   Lee, Sang Do   Uh, Soo Taek   Kim, Yong Hoon   Park, Choon Sik  

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  • Systems Metabolic Engineering Strategies:Integrating Systems and Synthetic Biology with Metabolic Engineering

    Choi, Kyeong Rok   Jang, Woo Dae   Yang, Dongsoo   Cho, Jae Sung   Park, Dahyeon   Lee, Sang Yup  

    Metabolic engineering allows development of microbial strains efficiently producing chemicals and materials, but it requires much time, effort, and cost to make the strains industrially competitive. Systems metabolic engineering, which integrates tools and strategies of systems biology, synthetic biology, and evolutionary engineering with traditional metabolic engineering, has recently been used to facilitate development of high-performance strains. The past decade has witnessed this interdisciplinary strategy continuously being improved toward the development of industrially competitive overproducer strains. In this article, current trends in systems metabolic engineering including tools and strategies are reviewed, focusing on recent developments in selection of host strains, metabolic pathway reconstruction, tolerance enhancement, and metabolic flux optimization. Also, future challenges and prospects are discussed.
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  • Systems Metabolic Engineering Strategies: Integrating Systems and Synthetic Biology with Metabolic Engineering

    Choi, Kyeong Rok   Jang, Woo Dae   Yang, Dongsoo   Cho, Jae Sung   Park, Dahyeon   Lee, Sang Yup  

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  • Markerless gene knockout and integration to express heterologous biosynthetic gene clusters in Pseudomonas putida.

    Choi, Kyeong Rok   Cho, Jae Sung   Cho, In Jin   Park, Dahyeon   Lee, Sang Yup  

    Pseudomonas putida has gained much interest among metabolic engineers as a workhorse for producing valuable natural products. While a few gene knockout tools for P. putida have been reported, integration of heterologous genes into the chromosome of P. putida, an essential strategy to develop stable industrial strains producing heterologous bioproducts, requires development of a more efficient method. Current methods rely on time-consuming homologous recombination techniques and transposon-mediated random insertions. Here we report a RecET recombineering system for markerless integration of heterologous genes into the P. putida chromosome. The efficiency and capacity of the recombineering system were first demonstrated by knocking out various genetic loci on the P. putida chromosome with knockout lengths widely spanning 0.6-101.7=E2=80=AFkb. The RecET recombineering system developed here allowed successful integration of biosynthetic gene clusters for four proof-of-concept bioproducts, including protein, polyketide, isoprenoid, and amino acid derivative, into the target genetic locus of P. putida chromosome. The markerless recombineering system was completed by combining Cre/lox system and developing efficient plasmid curing systems, generating final strains free of antibiotic markers and plasmids. This markerless recombineering system for efficient gene knockout and integration will expedite metabolic engineering of P. putida, a bacterial host strain of increasing academic and industrial interest. Copyright =C2=A9 2018 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.
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  • Reconstruction of context-specific genome-scale metabolic models using multi-omics data to study metabolic rewiring

    Cho, Jae Sung   Gu, Changdai   Han, Taehee   Ryu, Jae Yong   Lee, Sang Yup  

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  • Uterine artery Doppler velocimetry in the prediction of adverse obstetric outcomes in unexplained MSAFP elevations

    Chung, Jae Eun   Cho, Jae Sung   Han, Sung Shik   Park, Yong Won   Kim, Jae Wook  

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