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Mystery of Biological Plastic Synthesis Machinery Unveiled
Plastics and other polymers are used every day. These polymers are mostly made from fossil resources by refining petrochemicals. On the other hand, many microorganisms naturally synthesize polyesters known as polyhydroxyalkanoates (PHAs) as distinct granules inside cells.
PHAs are a family of microbial polyesters that have attracted much attention as biodegradable and biocompatible plastics and elastomers that can substitute petrochemical counterparts. There have been numerous papers and patents on gene cloning and metabolic engineering of PHA biosynthetic machineries, biochemical studies, and production of PHAs; simple Google search with “polyhydroxyalkanoates” yielded returns of 223,000 document pages. PHAs have always been considered amazing examples of biological polymer synthesis. It is astounding to see PHAs of 500 kDa to sometimes as high as 10,000 kDa can be synthesized in vivo by PHA synthase, the key polymerizing enzyme in PHA biosynthesis. They have attracted great interest in determining the crystal structure of PHA synthase over the last 30 years, but unfortunately without success. Thus, the characteristics and molecular mechanisms of PHA synthase were under a dark veil.
In two papers published back-to-back in Biotechnology Journal online on November 30, 2016, a Korean research team led by Professor Kyung-Jin Kim at Kyungpook National University and Distinguished Professor Sang Yup Lee at the Korea Advanced Institute of Science and Technology (KAIST) described the crystal structure of PHA synthase from Ralstonia eutropha, the best studied bacterium for PHA production, and reported the structural basis for the detailed molecular mechanisms of PHA biosynthesis. The crystal structure has been deposited to Protein Data Bank in February 2016. After deciphering the crystal structure of the catalytic domain of PHA synthase, in addition to other structural studies on whole enzyme and related proteins, the research team also performed experiments to elucidate the mechanisms of the enzyme reaction, validating detailed structures, enzyme engineering, and also N-terminal domain studies among others.
Through several biochemical studies based on crystal structure, the authors show that PHA synthase exists as a dimer and is divided into two distinct domains, the N-terminal domain (RePhaC1ND) and the C-terminal domain (RePhaC1CD). The RePhaC1CD catalyzes the polymerization reaction via a non-processive ping-pong mechanism using a Cys-His-Asp catalytic triad. The two catalytic sites of the RePhaC1CD dimer are positioned 33.4 Å apart, suggesting that the polymerization reaction occurs independently at each site. This study also presents the structure-based mechanisms for substrate specificities of various PHA synthases from different classes.
Professor Sang Yup Lee, who has worked on this topic for more than 20 years, said,
“The results and information presented in these two papers have long been awaited not only in the PHA community, but also metabolic engineering, bacteriology/microbiology, and in general biological sciences communities. The structural information on PHA synthase together with the recently deciphered reaction mechanisms will be valuable for understanding the detailed mechanisms of biosynthesizing this important energy/redox storage material, and also for the rational engineering of PHA synthases to produce designer bioplastics from various monomers more efficiently.”
Indeed, these two papers published in Biotechnology Journal finally reveal the 30-year mystery of machinery of biological polyester synthesis, and will serve as the essential compass in creating designer and more efficient bioplastic machineries.
References:
Jieun Kim, Yeo-Jin Kim, So Young Choi, Sang Yup Lee and Kyung-Jin Kim. “Crystal structure of Ralstonia eutropha polyhydroxyalkanoate synthase C-terminal domain and reaction mechanisms” Biotechnology Journal DOI: 10.1002/biot.201600648
http://onlinelibrary.wiley.com/doi/10.1002/biot.201600648/abstract
Yeo-Jin Kim, So Young Choi, Jieun Kim, Kyeong Sik Jin, Sang Yup Lee and Kyung-Jin Kim. “Structure and function of the N-terminal domain of Ralstonia eutropha polyhydroxyalkanoate synthase, and the proposed structure and mechanisms of the whole enzyme” Biotechnology Journal DOI: 10.1002/biot.201600649
http://onlinelibrary.wiley.com/doi/10.1002/biot.201600649/abstract
2016.12.02 View 9005 -
Professor Lee Co-chairs the Global Future Councils on Biotechnology of the WEF
The World Economic Forum (WEF) established a new global network of the world’s leading experts, “The Annual Meeting of the Global Future Councils,” to explore innovative solutions for the most pressing global challenges. The Councils’ first meeting took place on November 13-14, 2016, in Dubai, the United Arab Emirates (UAE). Some 25 nations joined as member states. The Councils have 35 committees.
Over 700 global leaders in business, government, civil society and academia gathered at the inaugural meeting to “develop ideas and strategies to prepare the world for the Fourth Industrial Revolution, with topics including smart cities, robotics, and the future of mobility,” according to a statement issued by the WEF.
Distinguished Professor Sang Yup Lee of Chemical and Biomolecular Engineering at KAIST was appointed to co-chair one of the Councils' committees, The Annual Meeting of the Global Future Councils on Biotechnology, for two years. The other chairperson is Dr. Feng Zhang, a professor of Biomedical Engineering at the Massachusetts Institute of Technology (MIT), who played a critical role in the development of optogenetics and CRISPR technologies.
The Biotechnology Committee consists of 24 globally recognized professionals in life sciences, law, ethics and policy including Thomas Connelly, the executive director of the American Chemical Society, Tina Fano, the executive vice president of Novozymes, and Mostafa Ronaghi, the chief technology officer of Illumina.
Professor Lee also serves as a committee member of The Annual Meeting of the Global Future Councils on the Fourth Industrial Revolution.
“Life sciences and engineering will receive more attention as a key element of the Fourth Industrial Revolution that the global society as a whole has been experiencing now. Together with thought leaders gathered worldwide, I will join the international community’s concerted efforts to address issues of importance that impact greatly on the future of humanity,” Professor Lee said.
In addition, Professor Lee received the James E. Bailey Award 2016 from The Society for Biological Engineering on November 15, 2016. He is the first Asian researcher to be recognized for his contributions to the field of biotechnology.
2016.11.15 View 8017 -
Doctoral Student Receives the Best Paper Award from the International Metabolic Engineering Conference 2016
So Young Choi, a Ph.D. candidate at the Department of Chemical and Biomolecular Engineering at KAIST, received the Student and Young Investigator Poster Award at the 11th International Metabolic Engineering Conference held in Awaji, Japan on June 26-30.
Choi received the award for her research on one-step fermentative production of Poly(lactate-co-glycolate) (PLGA) from carbohydrates in Escherichia coli, which was published in the April 2016 issue of Nature Biotechnology.
In her paper, she presented a novel technology to synthesize PLGA, a non-natural copolymer, through a biological production process. Because of its biodegradability, non-toxicity, and biocompatibility, PLGA is widely used in biomedical and therapeutic applications, including surgical sutures, prosthetic devices, drug delivery, and tissue engineering.
Employing a metabolic engineering approach, Choi manipulated the metabolic pathway of an Escherichia coli bacterium to convert glucose and xylose into the biosynthesis of PLGA within the cell. Previously, PLGA could be obtained only through chemical synthesis.
Choi said, “I’m thrilled to receive an award from a flagship conference of my research field. Mindful of this recognition, I will continue my research to produce meaningful results, thereby contributing to the development of science and technology in Korea.”
The International Metabolic Engineering Conference is a leading professional gathering where state-of-the-art developments and achievements made in the field of metabolic engineering are shared. With the participation of about 400 professionals from all around the world, the conference participants discussed this year’s theme of “Design, Synthesis and System Integration for Metabolic Engineering.”
2016.07.07 View 10075 -
Non-Natural Biomedical Polymers Produced from Microorganisms
KAIST researchers have developed metabolically engineered Escherichia coli strains to synthesize non-natural, biomedically important polymers including poly(lactate-co-glycolate) (PLGA), previously considered impossible to obtain from biobased materials.
Renewable non-food biomass could potentially replace petrochemical raw materials to produce energy sources, useful chemicals, or a vast array of petroleum-based end products such as plastics, lubricants, paints, fertilizers, and vitamin capsules. In recent years, biorefineries which transform non-edible biomass into fuel, heat, power, chemicals, and materials have received a great deal of attention as a sustainable alternative to decreasing the reliance on fossil fuels.
A research team headed by Distinguished Professor Sang Yup Lee of the Chemical and Biomolecular Engineering Department at KAIST has established a biorefinery system to create non-natural polymers from natural sources, allowing various plastics to be made in an environmentally-friendly and sustainable manner. The research results were published online in Nature Biotechnology on March 7, 2016. The print version will be issued in April 2016.
The research team adopted a systems metabolic engineering approach to develop a microorganism that can produce diverse non-natural, biomedically important polymers and succeeded in synthesizing poly(lactate-co-glycolate) (PLGA), a copolymer of two different polymer monomers, lactic and glycolic acid. PLGA is biodegradable, biocompatible, and non-toxic, and has been widely used in biomedical and therapeutic applications such as surgical sutures, prosthetic devices, drug delivery, and tissue engineering.
Inspired by the biosynthesis process for polyhydroxyalkanoates (PHAs), biologically-derived polyesters produced in nature by the bacterial fermentation of sugar or lipids, the research team designed a metabolic pathway for the biosynthesis of PLGA through microbial fermentation directly from carbohydrates in Escherichia coli (E. coli) strains.
The team had previously reported a recombinant E. coli producing PLGA by using the glyoxylate shunt pathway for the generation of glycolate from glucose, which was disclosed in their patents KR10-1575585-0000 (filing date of March 11, 2011), US08883463 and JP5820363. However, they discovered that the polymer content and glycolate fraction of PLGA could not be significantly enhanced via further engineering techniques. Thus, in this research, the team introduced a heterologous pathway to produce glycolate from xylose and succeeded in developing the recombinant E. coli producing PLGA and various novel copolymers much more efficiently.
In order to produce PLGA by microbial fermentation directly from carbohydrates, the team incorporated external and engineered enzymes as catalysts to co-polymerize PLGA while establishing a few additional metabolic pathways for the biosynthesis to produce a range of different non-natural polymers, some for the first time. This bio-based synthetic process for PLGA and other polymers could substitute for the existing complicated chemical production that involves the preparation and purification of precursors, chemical polymerization processes, and the elimination of metal catalysts.
Professor Lee and his team performed in silico genome-scale metabolic simulations of the E. coli cell to predict and analyze changes in the metabolic fluxes of cells which were caused by the introduction of external metabolic pathways. Based on these results, genes are manipulated to optimize metabolic fluxes by eliminating the genes responsible for byproducts formation and enhancing the expression levels of certain genes, thereby achieving the effective production of target polymers as well as stimulating cell growth.
The team utilized the structural basis of broad substrate specificity of the key synthesizing enzyme, PHA synthase, to incorporate various co-monomers with main and side chains of different lengths. These monomers were produced inside the cell by metabolic engineering, and then copolymerized to improve the material properties of PLGA. As a result, a variety of PLGA copolymers with different monomer compositions such as the US Food and Drug Administration (FDA)-approved monomers, 3-hydroxyburate, 4-hydroxyburate, and 6-hydroxyhexanoate, were produced. Newly applied bioplastics such as 5-hydroxyvalerate and 2-hydroxyisovalerate were also made.
The team employed a systems metabolic engineering application which, according to the researchers, is the first successful example of biological production of PGLA and several novel copolymers from renewable biomass by one-step direct fermentation of metabolically engineered E.coli.
Professor Lee said, “We presented important findings that non-natural polymers, such as PLGA which is commonly used for drug delivery or biomedical devices, were produced by a metabolically engineered gut bacterium. Our research is meaningful in that it proposes a platform strategy in metabolic engineering, which can be further utilized in the development of numerous non-natural, useful polymers.”
Director Ilsub Baek at the Platform Technology Division of the Ministry of Science, ICT and Future Planning of Korea, who oversees the Technology Development Program to Solve Climate Change, said, “Professor Lee has led one of our research projects, the Systems Metabolic Engineering for Biorefineries, which began as part of the Ministry’s Technology Development Program to Solve Climate Change. He and his team have continuously achieved promising results and been attracting greater interest from the global scientific community. As climate change technology grows more important, this research on the biological production of non-natural, high value polymers will have a great impact on science and industry.”
The title of the research paper is “One-step Fermentative Production of Poly(lactate-co-glycolate) from Carbohydrates in Escherichia coli (DOI: 10.1038/nbt.3485).” The lead authors are So Young Choi, a Ph.D. candidate in the Department of Chemical and Biomolecular Engineering at KAIST, and Si Jae Park, Assistant Professor of the Environmental Engineering and Energy Department at Myongji University. Won Jun Kim and Jung Eun Yang, both doctoral students in the Department of Chemical and Biomolecular Engineering at KAIST, also participated in the research.
This research was supported by the Technology Development Program to Solve Climate Change’s research project titled “Systems Metabolic Engineering for Biorefineries” from the Ministry of Science, ICT and Future Planning through the National Research Foundation of Korea (NRF-2012M1A2A2026556).
Figure: Production of PLGA and Other Non-Natural Copolymers
This schematic diagram shows the overall conceptualization of how metabolically engineered E. coli produced a variety of PLGAs with different monomer compositions, proposing the chemosynthetic process of non-natural polymers from biomass. The non-natural polymer PLGA and its other copolymers, which were produced by engineered bacteria developed by taking a systems metabolic engineering approach, accumulate in granule forms within a cell.
2016.03.08 View 10869 -
Asia Pacific Biotech News' Special Coverage of Korean Biotechnology
The Asia Pacific Biotech News covered five major biotechnology research projects sponsored by the Korean government in the areas of biofuels, biomedicine, bio-nano healthcare, and biorefinery.
The Asia Pacific Biotech News (APBN), a monthly magazine based in Singapore, which offers comprehensive reports on the fields of pharmaceuticals, healthcare, and biotechnology, recently published a special feature on Korea’s biotechnology research and development (R&D) programs.
The magazine feature selected five research programs sponsored by the Korean government, which are either part of the Global Frontier or the Climate Change Technology Development Projects.
The programs are:
Systems Metabolic Engineering Research: Distinguished Professor Sang Yup Lee
of the Chemical and Biomolecular Engineering Department at the Korea Advanced
Institute of Science and Technology (KAIST) has been leading a research group to
develop biorefining technology using renewable non-food biomass to produce
chemicals, fuels, and materials that were largely drawn from fossil resources
through petrochemical refinery processes. Applying a systems metabolic
engineering approach, the group succeeded in modifying the metabolic pathways of
microorganisms. As a result, they produced, for the first time in the world,
engineered plastic raw materials and gasoline. The team also developed a technique
to produce butanol and succinic acid with a higher titer and yield using metabolically
engineered microorganisms.
Next-generation Biomass Research: Under the leadership of Professor Yong-
Keun Chang of the Chemical and Biomolecular Engineering Department at KAIST,
the research project, which belongs to the Global Frontier Project, develops biofuels
and bioproducts utilizing microalgae typically found in water and other marine
systems.
Convergence Research for Biomedicine: Professor Sung-Hoon Kim of Seoul
National University leads this project that develops targeted new drugs based on
convergence research strategies.
Bionano Healthcare Chip Research: Director Bong-Hyun Chung of the Korea
Research Institute of Bioscience and Biotechnology has integrated information and
communications technology, nanotechnology, and biotechnology to develop a
diagnostic kit that can screen toxic germs, virus, and toxic materials in a prompt
and accurate manner.
Biosynergy Research: Led by Professor Do-Hun Lee of the Bio and Brain
Engineering Department at KAIST, this research project develops new treatments
with a multi-target, multi-component approach in the context of systems biology
through an analysis of synergistic reactions between multi-compounds in traditional
East Asian medicine and human metabolites. In East Asian medicine, treatment and
caring of the human body are considered analogous to the politics of governing a
nation. Based on such system, the research focuses on designing a foundation for
the integration of traditional medicine with modern drug discovery and development.
Director Ilsub Baek at the Platform Technology Division of the Ministry of Science, ICT and Future Planning, Republic of Korea, who is responsible for the Global Frontier Program and the Technology to Solve Climate Change, said, “It is great to see that Asia Pacific Biotech News published an extensive coverage of Korea’s several key research programs on biotechnology as its first issue of this year. I am sure that these programs will lead to great outcomes to solve many worldwide pending issues including climate change and healthcare in the aging society.”
Professor Sang Yup Lee, who served as an editor of the feature, said, “At the request of the magazine, we have already published lead articles on our biotechnology research three times in the past in 2002, 2006, and 2011. I am pleased to see continued coverage of Korean biotechnology by the magazine because it recognizes the excellence of our research. Biotechnology has emerged as one of the strong fields that addresses important global issues such as climate change and sustainability.”
2016.02.04 View 11338 -
IdeasLab Presents Biotechnology Solutions for Aging Populations at 2016 Davos Forum
KAIST researchers will discuss how biological sciences and health technologies can address challenges and opportunities posed by aging populations in an era of increasing longevity.
Many countries around the world today are experiencing the rapid growth of aging populations, with a decline in fertility rate and longer life expectancy.
At this year's Annual Meeting of the World Economic Forum (a.k.a. Davos Forum) on January 20-23, 2016 in Davos-Klosters, Switzerland, four researchers in the field of biological sciences and biotechnology at the Korea Advanced Institute of Science and Technology (KAIST) will discuss the implications of an aging population and explore possible solutions to provide better health care services to the elderly.
KAIST will host an IdeasLab twice on the theme "Biotechnology Solutions for Ageing Populations" on January 21st and 23rd, respectively.
Professor Byung-Kwan Cho of the Biological Sciences Department will give a presentation on "Rejuvenation via the Microbiome," explaining how microorganisms in the human gut play an important role in preventing aging, or even rejuvenating it.
Distinguished Professor Sang Yup Lee of the Chemical and Biomolecular Engineering Department will talk about "Traditional Medicine Reimagined through Modern Systems Biology." Professor Lee will introduce his research results published in Nature Biotechnology (March 6, 2015) and some more new results. He discovered the mechanisms of traditional oriental medicine's (TOM) efficacy by applying systems biology to study structural similarities between natural and nontoxic multi-compounds in the medicine and human metabolites. He will discuss TOM's multi-target approach, which is based on the synergistic combinations of multi-compounds to treat symptoms of a disease, can contribute to the development of new drugs, cosmetics, and nutrients.
Professor Youn-Kyung Lim of the Industrial Design Department will speak about a mobile and the Internet of Things-based health care service called "Dr. M" in her presentation on "Advanced Mobile Healthcare Systems."
Professor Daesoo Kim of the Biological Sciences Department will share his research on human's happiness and greed in the context of nueroscience and behavioral and biological sciences in a talk entitled "A Neural Switch for Being Happy with Less on a Crowded Planet."
KAIST has hosted IdeasLabs several times at the Summer Davos Forum in China, but this is the first time it will participate in the Davos Forum in January.
Professor Lee said, "Just like climate change, the issue of how to address aging populations has become a major global issue. We will share some exciting research results and hope to have in depth discussion on this issue with the leaders attending the Davos Forum. KAIST will engage actively in finding solutions that benefit not only Korea but also the international community."
2016.01.19 View 10098 -
Establishment of System Metabolic Engineering Strategies
Although conventional petrochemical processes have generated chemicals and materials which have been useful to mankind, they have also triggered a variety of environmental problems including climate change and relied too much on nonrenewable natural resources. To ameliorate this, researchers have actively pursued the development of industrial microbial strains around the globe in order to overproduce industrially useful chemicals and materials from microbes using renewable biomass. This discipline is called metabolic engineering.
Thanks to advances in genetic engineering and our knowledge of cellular metabolism, conventional metabolic engineering efforts have succeeded to a certain extent in developing microbial strains that overproduce bioproducts at an industrial level. However, many metabolic engineering projects launched in academic labs do not reach commercial markets due to a failure to fully integrate industrial bioprocesses.
In response to this, Distinguished Professor Sang Yup Lee and Dr. Hyun Uk Kim, both from the Department of Chemical and Biomolecular Engineering at KAIST, have recently suggested ten general strategies of systems metabolic engineering to successfully develop industrial microbial strains. Systems metabolic engineering differs from conventional metabolic engineering by incorporating traditional metabolic engineering approaches along with tools of other fields, such as systems biology, synthetic biology, and molecular evolution.
The ten strategies of systems metabolic engineering have been featured in Nature Biotechnology released online in October 2015, which is entitled "Systems strategies for developing industrial microbial strains."
The strategies cover economic, state-of-the-art biological techniques and traditional bioprocess aspects. Specifically, they consist of: 1) project design including economic evaluation of a target bioproduct; 2) selection of host strains to be used for overproduction of a bioproduct; 3) metabolic pathway reconstruction for bioproducts that are not naturally produced in the selected host strains; 4) increasing tolerance of a host strain against the bioproduct; 5) removing negative regulatory circuits in the microbial host limiting overproduction of a bioproduct; 6) rerouting intracellular fluxes to optimize cofactor and precursor availability necessary for the bioproduct formation; 7) diagnosing and optimizing metabolic fluxes towards product formation; 8) diagnosis and optimization of microbial culture conditions including carbon sources; 9) system-wide gene manipulation to further increase the host strain's production performance using high-throughput genome-scale engineering and computational tools; and 10) scale-up fermentation of the developed strain and diagnosis for the reproducibility of the strain's production performance.
These ten strategies were articulated with successful examples of the production of L-arginine using Corynebacterium glutamicum, 1,4-butanediol using Escherichia coli, and L-lysine and bio-nylon using C. glutamicum.
Professor Sang Yup Lee said, "At the moment, the chance of commercializing microbial strains developed in academic labs is very low. The strategies of systems metabolic engineering outlined in this analysis can serve as guidelines when developing industrial microbial strains. We hope that these strategies contribute to improving opportunities to commercialize microbial strains developed in academic labs with drastically reduced costs and efforts, and that a large fraction of petroleum-based processes will be replaced with sustainable bioprocesses."
Lee S. Y. & Kim, H. U. Systems Strategies for Developing Industrial Microbial Strains. Nature Biotechnology (2015).
This work was supported by the Technology Development Program to Solve Climate Change on Systems Metabolic Engineering for Biorefineries (NRF-2012M1A2A2026556) and by the Intelligent Synthetic Biology Center through the Global Frontier Project (2011-0031963) from the Ministry of Science, ICT and Future Planning (MSIP), Korea, and through the National Research Foundation (NRF) of Korea. This work was also supported by the Novo Nordisk Foundation.
Picture: Concept of the Systems Metabolic Engineering Framework
(a) Three major bioprocess stages (b) Considerations in systems metabolic engineering to optimize the whole bioprocess. List of considerations for the strain development and fermentation contribute to improving microbial strain's production performance (red), whereas those for the separation and purification help in reducing overall operation costs by facilitating the downstream process (blue). Some of the considerations can be repeated in the course of systems metabolic engineering.
2015.10.19 View 9767 -
Professor Ki-Jun Jeong Wins the 2015 Dam Yeun Academic Award
The 11th Dam Yeun Academic Award presented by the Korean Society for Biotechnology and Bioengineering (KSBB) to a biologist under 45 years old went to Professor Ki-Jun Jeong of the Chemical and Biomolecular Engineering Department at KAIST.
The award ceremony took place on October 13, 2015, at the annual conference of KSBB held at Songdo Convensia in Incheon City.
Each year KSBB announces the recipient of the award based on the publications by researchers in the last five years at peer-reviewed international journals or KSBB Journal as well as the record of patent registration and technology transfers.
Professor Jeong is recognized for his pioneering research in protein, antibody, cellular engineering, and protein displays and chips.
2015.10.19 View 7694 -
KAIST and Oberthur Technologies Agree for Research and Development in Mobile Security
Professor Kwangjo Kim of the School of Computing at KAIST has signed a research and development (R&D) agreement with Marc Bertin, the Chief Technology Officer of Oberthur Technologies (OT), a French security solutions firm, on September 18, 2015 in Paris.
Under the agreement, KAIST and OT will conduct joint research on mobile security as well as implement an internship program for KAIST graduate students to work either at OT’s R&D center in Korea or in France.
OT has established a research center in Korea in July 2014, which was the fourth of its research centers in Asia.
Professor Kim said, “Our goal at KAIST is to cultivate top-level security experts in security technologies. By partnering with such a leader in security technologies as OT, we know that we will both help shape tomorrow’s security solution for the IoT (Internet of Things) space.”
In the picture, Professor Kwangjo Kim (left) shakes hands with Marc Bertin, the Chief Technology Officer of Oberthur Technologies (right), after the signing of a memorandum of understanding.
2015.09.24 View 6736 -
Nature Biotechnology Nominates Sang Yup Lee of KAIST for Top 20 Translational Researchers of 2014
Nature Biotechnology, recognized as the most prestigious journal in the field of biotechnology, has released today its list of the Top 20 Translational Researchers of 2014. Distinguished Professor Sang Yup Lee of the Department of Chemical and Biomolecular Engineering at KAIST (Korea Advanced Institute of Science and Technology) ranked seventh in the list. He is the only Asian researcher listed.
The journal, in partnership with IP Checkups, a patent analytics firm, presents an annual ranking of researchers based on their paper and patent output. The list includes, among others, each researcher’s most-cited patent in the past five years and their H index, a measurement to evaluate the impact of a researcher’s published work utilizing citation analysis. (More details can be found at http://www.nature.com/bioent/2015/150801/full/bioe.2015.9.html.)
American institutions made up the majority of the list, with 18 universities and research institutes, and the remainder was filled by KAIST in Korea and the Commonwealth Scientific and Industrial Research Organization (CSIRO) in Australia.
Globally known as a leading researcher in systems metabolic engineering, Professor Lee has published more than 500 journal papers and 580 patents. He has received many awards, including the Citation Classic Award, Elmer Gaden Award, Merck Metabolic Engineering Award, ACS Marvin Johnson Award, SIMB Charles Thom Award, POSCO TJ Park Prize, Amgen Biochemical Engineering Award, and the Ho Am Prize in Engineering.
2015.08.27 View 8811 -
Professor Sang-Yup Lee Receives the Order of Service Merit Red Stripes from the Korean Government
The government of the Republic of Korea named Professor Sang-Yup Lee of the Department of Chemical and Bio-molecular Engineering at KAIST as the fiftieth recipient of the Order of Service Merit Red Stripes on May 19, 2015.
This medal is awarded to government employees, officials, and teachers in recognition of their contributions to public services including education.
Professor Lee is regarded as a leading scientist in the field of metabolic engineering, genomics, proteomics, metabolomics, and bioinformatics on microorganism producing various primary and secondary metabolites. He contributed significantly to the advancement of bio-based engineering research in Korea.
In addition, his research in microorganism metabolic engineering propelled him to the front of his field, making him the world’s founder of systems metabolic engineering, inventing numerous technologies in strain development.
Professor Lee has received many patent rights in bioprocess engineering. While at KAIST, he applied for 585 patents and registered 227 patents. In particular, he has applied for 135 patents and registered 99 patents in the past five years, successfully turning research results into commercial applications.
Professor Lee said, “I’m glad to contribute to the development of Korean science and technology as a researcher and teacher. I would like to share this honor with my students, master’s and doctoral students in particular, because without their support, it wouldn’t have been possible to pull off the highest level of research results recognized by this medal.”
2015.05.21 View 7259 -
KAIST Researchers Develops Hyper-Stretchable Elastic-Composite Energy Harvester
A research team led by Professor Keon Jae Lee (http://fand.kaist.ac.kr) of the Department of Materials Science and Engineering at KAIST has developed a hyper-stretchable elastic-composite energy harvesting device called a nanogenerator.
Flexible electronics have come into the market and are enabling new technologies like flexible displays in mobile phone, wearable electronics, and the Internet of Things (IoTs). However, is the degree of flexibility enough for most applications? For many flexible devices, elasticity is a very important issue. For example, wearable/biomedical devices and electronic skins (e-skins) should stretch to conform to arbitrarily curved surfaces and moving body parts such as joints, diaphragms, and tendons. They must be able to withstand the repeated and prolonged mechanical stresses of stretching. In particular, the development of elastic energy devices is regarded as critical to establish power supplies in stretchable applications. Although several researchers have explored diverse stretchable electronics, due to the absence of the appropriate device structures and correspondingly electrodes, researchers have not developed ultra-stretchable and fully-reversible energy conversion devices properly.
Recently, researchers from KAIST and Seoul National University (SNU) have collaborated and demonstrated a facile methodology to obtain a high-performance and hyper-stretchable elastic-composite generator (SEG) using very long silver nanowire-based stretchable electrodes. Their stretchable piezoelectric generator can harvest mechanical energy to produce high power output (~4 V) with large elasticity (~250%) and excellent durability (over 104 cycles). These noteworthy results were achieved by the non-destructive stress- relaxation ability of the unique electrodes as well as the good piezoelectricity of the device components. The new SEG can be applied to a wide-variety of wearable energy-harvesters to transduce biomechanical-stretching energy from the body (or machines) to electrical energy.
Professor Lee said, “This exciting approach introduces an ultra-stretchable piezoelectric generator. It can open avenues for power supplies in universal wearable and biomedical applications as well as self-powered ultra-stretchable electronics.”
This result was published online in the March issue of Advanced Materials, which is entitled “A Hyper-Stretchable Elastic-Composite Energy Harvester.”
YouTube Link: “A hyper-stretchable energy harvester”
https://www.youtube.com/watch?v=EBByFvPVRiU&feature=youtu.be
Figure: Top row: Schematics of hyper-stretchable elastic-composite generator enabled by very long silver nanowire-based stretchable electrodes.
Bottom row: The SEG energy harvester stretched by human hands over 200% strain.
2015.04.14 View 12816