IoT
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KAIST Develops IoT Platform for Food Safety
A research team led by the KAIST Auto-ID Labs developed a GS1 international standard-based IoTs infrastructure platform dubbed Oliot (Open Language of Internet of Things). This platform will be applied to Wanju Local Food, the nation’s largest cooperative, and will be in operation from April 5.
A total of eleven organizations participated in the development of Oliot, with KAIST as the center. This consortium is based on the GS1 international standard-based Oliot platform, which allows collecting and sharing data along the entire process of agrifood from production to processing, distribution, and consumption. It aims at increasing farm incomes and establishing a global ecosystem of domestic agriculture and stockbreeding that provides safe food.
Wanju Local Food is now the world’s first local food co-op with a traceability system from the initial stage of production planning to end sales based on GS1 international standards, which will ensure food safety.
KAIST has been sharing Oliot data in order to apply it to industries around the world. As of April 2018, approximately 900 enterprises and developers from more than 100 countries have downloaded it.
Professor Daeyoung Kim from the School of Computing, who is also Research Director of Auto-ID Labs said, “We are planning to disseminate Oliot to local food cooperatives throughout the nation. We will also cooperate with other countries, like China, Holland, and Hong Kong to create a better ecosystem for the global food industry.
“We are currently collaborating with related business to converge Oliot with AI or blockchain technology that can be applied to various services, such as healthcare and smart factories. Its tangible outcome will be revealed soon,” he added.
Auto-ID Labs are a global research consortium of six academic institutions that research and develop new technologies for advancing global commerce, partnering with GS1 (Global Standard 1), a non-profit organization that established standards for global commerce such as introducing barcodes to the retail industry. The Auto-ID Labs include MIT, University of Cambridge, Keio University, Fudan University, ETH Zurich/University of St. Gallen, and KAIST.
The consortium was supported by the Ministry of Science and ICT as well as the Institute for Information and Communications Technology Promotion for three years from 2015.
The launching of Oliot at Wanju Local Food will be held on April 5.
2018.04.03 View 4012 -
In Jin Cho Earned the Best Poster Prize at ME Summit 2017
In Jin Cho, a Ph.D. student in the Department of Chemical and Biomolecular Engineering at KAIST received the best poster prize at the International Metabolic Engineering Summit 2017 held on October 24 in Beijing, China.
The International Metabolic Engineering Summit is a global conference where scientists and corporate researchers in the field of metabolic engineering present their latest research outcomes and build networks.
At this year’s summit, about 500 researchers from around the world participated in active academic exchanges, including giving keynote speeches and presenting posters.
During the poster session, the summit selects one person for the KeAi-synthetic and Systems Biotechnology Poster Award, two for Microbial Cell Factories Poster Awards, and three for Biotechnology Journal Poster Awards among the posters presented by graduate students, post-doctoral fellows and researchers. Cho received the KeAi-synthetic and Systems Biotechnology Poster Award. Her winning poster is on the biotransformation of p-xylene to terephthalic acid using engineered Escherichia coli.
Terephthalic acid is generally produced by p-xylene oxidation; however, this process requires a high temperature and pressure as well as a toxic catalyst during the reaction process.
Cho and Ziwei Luo, a Ph.D. student at KAIST, co-conducted the research and developed a successful biological conversion process. Compared to the existing chemical process, it does not require a high temperature and pressure; and it is environmentally friendly with a relatively high conversion rate of approximately 97%.
Cho’s advisor, Distinguished Professor Sang Yup Lee said, “Further research on glucose-derived terephthalic acid will enable us to produce biomass-based eco-friendly terephthalic acid through engineered Escherichia coli.”
2017.10.31 View 3698 -
Distinguished Professor Lee Named International Fellow of the CAS
Distinguished Professor Sang Yup Lee from the Department of Chemical and Biomolecular Engineering at KAIST was awarded the title of distinguished professor and international fellow from the Chinese Academy of Sciences (CAS), and honorary professor from its affiliated organization the Tianjin Institute of Industrial Biotechnology (TIB).
The CAS recognized Distinguished Professor Lee for his significant contributions to biotechnology. He has made significant pioneering academic achievements in the area of systems metabolic engineering, which produces useful chemicals from microorganisms. Not only did he develop the first and best source technology in that field, but also came out with processes for the production of biofuel and environmentally-friendly chemicals.”
As a global leader in systems metabolic engineering, Distinguished Professor Lee has also been appointed as an honorary professor at Jiangnan University in Wuxi, China.
Distinguished Professor Lee was listed in the ‘Top 20 Translational Researchers of 2014’ selected by the renowned international journal Nature Biotechnology. Moreover, he was the first Asian recipient of the James E. Bailey Award in 2016 and Marvin J. Johnson Award in 2012, which are given to scholars in the field of biotechnology.
He is also one of 13 global scientists who are foreign members of the renowned academic societies the National Academy of Engineering and the National Academy of Sciences in the US. Furthermore, he received the ‘2017 Korea Best Scientist Award’ from the president of Korea in July. Finally, his founding field, systems metabolic engineering, was chosen as one of the ‘Top 10 Emerging Technologies of 2016’ by the World Economic Forum.
The Chinese Academy of Sciences, established in November 1949, is an academic organization that carries out research on basic sciences and natural sciences in China. It defined its science and technology system to include the fields of basic sciences, natural sciences, and high technology. While having a base in Beijing, its branch academies are located in 12 main cities along with 117 affiliates and 100 national key labs.
2017.10.26 View 4676 -
KAIST Researchers Receive Awards at the 13th Asian Congress on Biotechnology
(From left: Seon Young Park, Dr. So Young Choi, and Yoojin Choi)
Researchers in the laboratory of KAIST Distinguished Professor Sang Yup Lee from the Department of Chemical and Biomolecular Engineering swept awards at the 13th Asian Congress on Biotechnology held in Thailand last month. The conference awarded a total of eight prizes in the areas of best research and best poster presentation. This is an exceptional case in which members of one research team received almost half of the awards at an international conference.
Dr. So Young Choi received the Best Research Award, while Ph.D. candidates Yoojin Choi and Seon Young Park each received the Best Poster Presentation Award at the conference held in Khon Kaen, Thailand from July 23 to 27.
The Asian Congress on Biotechnology is an international conference in which scientists and industry experts in Asia and from around the world gather to present recent research findings in the field of biotechnology. At the conference, around 400 researchers in biotechnology from 25 countries, including Korea, gathered to present and discuss various research findings under the theme of “Bioinnovation and Bioeconomy.”
Distinguished Professor Sang Yup Lee attended the conference to give the opening plenary lecture on the topic of ‘Systems Strategies in Biotechnology.’ Professor Lee announced, “I have attended international conferences with students for the last 20 years, but this is the first in which my team received three awards at an international conference that only honors a total of eight awards, three for Best Research and five for Best Presentation.”
Dr. Choi presented research results on poly (lactate-co-glycolate) (PLGA) synthesis through a biological method using micro-organisms and received the Best Research Award. PLGA is a random copolymer of DL-lactic and glycolic acids and is a biopolymer widely used for biomedical applications. PLGA is biodegradable, biocompatible, and nontoxic, and thus has been approved by the US Food and Drug Administration (FDA) for its use in implants, drug delivery, and sutures.
Dr. Choi’s research was deemed to be innovative for synthesizing PLGA from glucose and xylose in cells through metabolic engineering of E.Coli. Dr. Choi received her Ph.D. under the supervision of Distinguished Professor Lee this February and is currently conducting post-doc research.
Ph.D. candidate Choi presented her research on the use of recombinant E.Coli for the biological synthesis of various nanoparticles and received the Best Poster Presentation award. Choi used recombinant E.Coli-expressing proteins and peptides that adsorb to heavy metals to biologically synthesize diverse metal nanoparticles such as single-nanoparticle including gold and silver, quantum dots, and magnetic nanoparticles for the first time. The synthesized nanoparticles can be used in the fields of bio-imaging, diagnosis, environment, and energy.
Ph.D. candidate Park, who also received the Best Poster Presentation award, synthesized and increased production of astanxanthin, a strong antioxidant found in nature, in E.Coli using metabolic engineering. Astanxanthin is a carotenoid pigment found in salmon and shrimp that widely used in health products and cosmetics.
2017.08.01 View 8010 -
Top 10 Emerging Technologies of 2017
The World Economic Forum’s Expert Network and Global Future Councils in collaboration with Scientific American and its Board of Advisors announced the top 10 emerging technologies of 2017 on June 26 in Dalian, China where the 2017 Summer Davos Forum is being held. Each technology was chosen for its potential to improve lives, transform industries, and safeguard the planet.
The KAIST delegation, headed by President Sung-Chul Shin, is participating in the forum’s diverse activities including IdeasLab and GULF (Global University Leaders Forum). KAIST is the only Korean representative participating in the IdeasLab. KAIST Distinguished Professor Sang Yup Lee of the Department of Chemical and Biomolecular Engineering, director of KAIST Institute, has served as a committee member of the Global Agenda Council on Emerging Technologies since 2012 and Global Future Council on the Fourth Industrial Revolution. He also chairs the Global Future Council on Biotechnologies.
Professor Lee said, “Very diverse technological breakthroughs were proposed for the final list of candidates. We made the final selections through very in-depth discussion with experts in each field.
We focused on the technologies which have a level of maturity that will enable them to be adopted widely within three to five years."
The top 10 emerging technologies are
(courtesy from https://
www.weforum.org/agenda/2017/06/these-are-the-top-10-emerging-technologies-of-2017):
2017 10대 기술.
1. Liquid biopsies
Liquid biopsies mark a step forward in the fight against cancer. First, they are an alternative where traditional tissue-based biopsies are not possible. Second, they provide a full spectrum of information compared to tissue samples, which only reflect the information available in the sample. Lastly, by homing in on circulating-tumor DNA (ctDNA), genetic material that routinely finds its way from cancer cells into the bloodstream, disease progression or resistance to treatment can be spotted much faster than otherwise relying on symptoms or imaging.
2. Harvesting clean water from air
The ability to extract clean water from air is not new, however existing techniques require high moisture levels and a lot of electricity. This is changing. A team from MIT and University of California, Berkeley has successfully tested a process using porous crystals that convert the water using no energy at all.
3. Deep learning for visual tasks
Computers are beginning to recognize images better than humans. Thanks to deep learning, an emerging field of artificial intelligence, computer-vision technologies are increasingly being used in applications as diverse as driving autonomous vehicles, medical diagnostics, damage assessment for insurance claims, and monitoring water levels and crop yield.
4. Liquid fuels from sunshine
Can we mimic the humble leaf to create artificial photosynthesis to generate and store energy? The prospects are looking increasingly positive. The answer lies in using sunlight-activated catalysts to split water molecules into water and hydrogen, and then using the same hydrogen to convert CO2 into hydrocarbons.
5. The Human Cell Atlas
An international collaboration aimed at deciphering the human body, called the Human Cell Atlas, was launched in October 2016. The project aims to identify every cell type in every tissue; learn exactly which genes, proteins, and other molecules are active in each type, and the processes which control that activity.
6. Precision farming
The Fourth Industrial Revolution is providing farmers with a new set of tools to boost crop yield and quality while reducing water and chemical use. Sensors, robots, GPS, mapping tools, and data-analytics software are all being used to customize the care that plants need.
7. Affordable catalysts for green vehicles
Progress is being made on a promising zero-emission technology, the hydrogen-fed fuel cell. Progress to date has been stymied by the high price of catalysts which contain platinum. However, much progress has been made in reducing reliance on this rare and expensive metal, and the latest developments involve catalysts that include no platinum, or in some cases no metal at all.
8. Genomic vaccines
Vaccines based on genes are superior to more conventional ones in a number of ways. They are faster to manufacture, which is crucial during violent outbreaks. Compared to manufacturing proteins in cell cultures or eggs, producing genetic material should also be simpler and less expensive.
9. Sustainable design of communities
Applying green construction to multiple buildings at once has the potential to revolutionize the amount of energy and water we consume. Sending locally-generated solar power to a smart microgrid could reduce electricity consumption by half and reduce carbon emissions to zero if a project currently under development at the University of California at Berkeley goes according to plan.
10. Quantum computing
Quantum computers’ almost limitless potential has only ever been matched by the difficulty and cost of their construction. This explains why today the small ones that have been built have not yet managed to exceed the power of supercomputers. But progress is being made and in 2016 the technology firm IBM provided public access to the first quantum computer in the cloud.
2017.06.28 View 7232 -
Distinguished Professor Lee Elected to the NAS
Distinguished Professor Sang Yup Lee of the Department of Chemical and Biomolecular Engineering was elected as a foreign associate to the US National Academy of Sciences (NAS) on May 2. The National Academy of Sciences elected 84 new members and 21 foreign associates in recognition of their distinguished and continuing achievements in their original research. Election to the Academy is widely regarded as one of the highest honors that a scientist can receive.
Professor Lee was also elected in 2010 as a member of the US National Academy of Engineering (NAE) for his leadership in microbial biotechnology and metabolic engineering, including the development of fermentation processes for biodegradable polymers and organic acids. Until 2016, there are only 12 people worldwide who are foreign associates of both NAS and NAE.
He is the first Korean elected to both prestigious academies, the NAS and the NAE in the US. Professor Lee is currently the dean of KAIST Institutes, the world leading institute for multi-and interdisciplinary research. He is also serving as co-chair of the Global Council on Biotechnology and member of the Global Future Council on the Fourth Industrial Revolution, the World Economic Forum.
2017.05.16 View 4183 -
Improving Silver Nanowires for FTCEs with Flash Light Interactions
Flexible transparent conducting electrodes (FTCEs) are an essential element of flexible optoelectronics for next-generation wearable displays, augmented reality (AR), and the Internet of Things (IoTs). Silver nanowires (Ag NWs) have received a great deal of attention as future FTCEs due to their great flexibility, material stability, and large-scale productivity. Despite these advantages, Ag NWs have drawbacks such as high wire-to-wire contact resistance and poor adhesion to substrates, resulting in severe power consumption and the delamination of FTCEs.
A research team led by Professor Keon Jae Lee of the Materials Science and Engineering Department at KAIST and Dr. Hong-Jin Park from BSP Inc., has developed high-performance Ag NWs (sheet resistance ~ 5 Ω/sq, transmittance 90 % at λ = 550 nm) with strong adhesion on plastic (interfacial energy of 30.7 J∙m-2) using flash light-material interactions.
The broad ultraviolet (UV) spectrum of a flash light enables the localized heating at the junctions of nanowires (NWs), which results in the fast and complete welding of Ag NWs. Consequently, the Ag NWs demonstrate six times higher conductivity than that of the pristine NWs. In addition, the near-infrared (NIR) of the flash lamp melted the interface between the Ag NWs and a polyethylene terephthalate (PET) substrate, dramatically enhancing the adhesion force of the Ag NWs to the PET by 310 %.
Professor Lee said, “Light interaction with nanomaterials is an important field for future flexible electronics since it can overcome thermal limit of plastics, and we are currently expanding our research into light-inorganic interactions.”
Meanwhile, BSP Inc., a laser manufacturing company and a collaborator of this work, has launched new flash lamp equipment for flexible applications based on the Professor Lee’s research.
The results of this work entitled “Flash-Induced Self-Limited Plasmonic Welding of Ag NW Network for Transparent Flexible Energy Harvester (DOI: 10.1002/adma.201603473)” were published in the February 2, 2017 issue of Advanced Materials as the cover article.
Professor Lee also contributed an invited review in the same journal of the April 3, 2017 online issue, “Laser-Material Interactions for Flexible Applications (DOI:10.1002/adma.201606586),” overviewing the recent advances in light interactions with flexible nanomaterials.
References
[1] Advanced Materials, February 2, 2017, Flash-Induced Self-Limited Plasmonic Welding of Ag NW network for Transparent Flexible Energy Harvester http://onlinelibrary.wiley.com/doi/10.1002/adma.201603473/epdf
[2] Advanced Materials, April 3, 2017, Laser-Material Interactions for Flexible Applications
http://onlinelibrary.wiley.com/doi/10.1002/adma.201606586/abstract
For further inquiries on research:
keonlee@kaist.ac.kr (Keon Jae Lee), hjpark@bsptech.co.kr (Hong-Jin Park)
Picture 1: Artistic Rendtition of Light Interaction with Nanomaterials
(This image shows flash-induced plasmonic interactions with nanowires to improve silver nanowires (Ag NWs).)
Picture 2: Ag NW/PET Film
(This picture shows the Ag NWs on a polyethylene terephthalate (PET) film after the flash-induced plasmonic thermal process.)
2017.04.05 View 6381 -
Professor Dongman Lee Wins the 2016 Korea Internet Award
Professor Dongman Lee of KAIST’s School of Computing received the 11th Korea Internet Award in the category of personal achievement on December 13 at the Creative Economy and Innovation Center in Gyeonggi province.
Hosted by the Ministry of Science, ICT and Future Planning of Korea, the Internet Award recognizes leaders in the Internet industry and their contributions.
Since 2010, Professor Lee has conducted research on the Internet of Things (IoT) platforms, resulting in the publication of five research papers in Science Citation Index (SCI) journals, ten papers in Korean journals, 30 best papers nominations at international conferences, and the registration of eleven patents. He has also worked on the creation of an IoT ecosystem through his research on object interworking platforms that can provide diverse user-customized services in the IoT environment.
His research team built a test bed for applicable IoT platforms on the 8th floor of the IT Convergence Center on campus to implement experiments and collect various data, thereby creating a foundation to carry out research projects in this field.
Professor Lee has helped the advancement of an Internet governance system in Korea by researching Internet governance policies, holding important posts in related academic societies including the Chairman of the Korea Internet Governance Alliance (KIGA) Council, and hosting major conferences such as the Asia Pacific Regional Internet Governance Forum (APrIGF).
2016.12.20 View 3756 -
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 5994 -
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 4374 -
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 7205 -
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 7333