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KAIST Researchers Suggest an Extraordinary Alternative to Petroleum-based PET - Bacteria!
< (From left) Dr. Cindy Pricilia, Ph.D. Candidate Cheon Woo Moon, Distinguished Professor Sang Yup Lee >
Currently, the world is suffering from environmental problems caused by plastic waste. The KAIST research team has succeeded in producing a microbial-based plastic that is biodegradable and can replace existing PET bottles, making it a hot topic.
Our university announced on the 7th of November that the research team of Distinguished Professor Sang Yup Lee of the Department of Chemical and Biomolecular Engineering has succeeded in developing a microbial strain that efficiently produces pseudoaromatic polyester monomer to replace polyethylene terephthalate (PET) using systems metabolic engineering.
Pseudoaromatic dicarboxylic acids have better physical properties and higher biodegradability than aromatic polyester (PET) when synthesized as polymers, and are attracting attention as an eco-friendly monomer* that can be synthesized into polymers. The production of pseudoaromatic dicarboxylic acids through chemical methods has the problems of low yield and selectivity, complex reaction conditions, and the generation of hazardous waste.
*Monomer: A material for making polymers, which is used to synthesize polymers by polymerizing monomers together
< Figure. Overview of pseudoaromatic dicarboxylic acid production using metabolically engineered C. glutamicum. >
To solve this problem, Professor Sang Yup Lee's research team used metabolic engineering to develop a microbial strain that efficiently produces five types of pseudoaromatic dicarboxylic acids, including 2-pyrone-4,6-dicarboxylic acid and four types of pyridine dicarboxylic acids (2,3-, 2,4-, 2,5-, 2,6-pyridine dicarboxylic acids), in Corynebacterium, a bacterium mainly used for amino acid production.
The research team used metabolic engineering techniques to build a platform microbial strain that enhances the metabolic flow of protocatechuic acid, which is used as a precursor for several pseudoaromatic dicarboxylic acids, and prevents the loss of precursors.
Based on this, the genetic manipulation target was discovered through transcriptome analysis, producing 76.17 g/L of 2-pyrone-4,6-dicarboxylic acid, and by newly discovering and constructing three types of pyridine dicarboxylic acid production metabolic pathways, successfully producing 2.79 g/L of 2,3-pyridine dicarboxylic acid, 0.49 g/L of 2,4-pyridine dicarboxylic acid, and 1.42 g/L of 2,5-pyridine dicarboxylic acid.
In addition, the research team confirmed the production of 15.01 g/L through the construction and reinforcement of the 2,6-pyridine dicarboxylic acid biosynthesis pathway, successfully producing a total of five similar aromatic dicarboxylic acids with high efficiency.
In conclusion, the team succeeded in producing 2,4-, 2,5-, and 2,6-pyridine dicarboxylic acids at the world's highest concentration. In particular, 2,4-, 2,5-pyridine dicarboxylic acid achieved production on the scale of g/L, which was previously produced in extremely small amounts (mg/L).
Based on this study, it is expected that it will be applied to various polyester production industrial processes, and it is also expected that it will be actively utilized in research on the production of similar aromatic polyesters.
Professor Sang Yup Lee, the corresponding author, said, “The significance lies in the fact that we have developed an eco-friendly technology that efficiently produces similar aromatic polyester monomers based on microorganisms,” and “This study will help the microorganism-based bio-monomer industry replace the petrochemical-based chemical industry in the future.”
The results of this study were published in the international academic journal, the Proceedings of the National Academy of Sciences of United States of America (PNAS) on October 30th.
※ Paper title: Metabolic engineering of Corynebacterium glutamicum for the production of pyrone and pyridine dicarboxylic acids
※ Author information: Jae Sung Cho (co-first author), Zi Wei Luo (co-first author), Cheon Woo Moon (co-first author), Cindy Prabowo (co-author), Sang Yup Lee (corresponding author) - a total of 5 people
This study was conducted with the support of the Development of Next-generation Biorefinery Platform Technologies for Leading Bio-based Chemicals Industry Project and the Development of Platform Technologies of Microbial Cell Factories for the Next-generation Biorefineries Project (Project leader: Professor Sang Yup Lee) from the National Research Foundation supported by the Ministry of Science and Technology and ICT of Korea.
2024.11.08 View 773 -
KAIST Develops Technology for the Precise Diagnosis of Electric Vehicle Batteries Using Small Currents
Accurately diagnosing the state of electric vehicle (EV) batteries is essential for their efficient management and safe use. KAIST researchers have developed a new technology that can diagnose and monitor the state of batteries with high precision using only small amounts of current, which is expected to maximize the batteries’ long-term stability and efficiency.
KAIST (represented by President Kwang Hyung Lee) announced on the 17th of October that a research team led by Professors Kyeongha Kwon and Sang-Gug Lee from the School of Electrical Engineering had developed electrochemical impedance spectroscopy (EIS) technology that can be used to improve the stability and performance of high-capacity batteries in electric vehicles.
EIS is a powerful tool that measures the impedance* magnitude and changes in a battery, allowing the evaluation of battery efficiency and loss. It is considered an important tool for assessing the state of charge (SOC) and state of health (SOH) of batteries. Additionally, it can be used to identify thermal characteristics, chemical/physical changes, predict battery life, and determine the causes of failures. *Battery Impedance: A measure of the resistance to current flow within the battery that is used to assess battery performance and condition.
However, traditional EIS equipment is expensive and complex, making it difficult to install, operate, and maintain. Moreover, due to sensitivity and precision limitations, applying current disturbances of several amperes (A) to a battery can cause significant electrical stress, increasing the risk of battery failure or fire and making it difficult to use in practice.
< Figure 1. Flow chart for diagnosis and prevention of unexpected combustion via the use of the electrochemical impedance spectroscopy (EIS) for the batteries for electric vehicles. >
To address this, the KAIST research team developed and validated a low-current EIS system for diagnosing the condition and health of high-capacity EV batteries. This EIS system can precisely measure battery impedance with low current disturbances (10mA), minimizing thermal effects and safety issues during the measurement process.
In addition, the system minimizes bulky and costly components, making it easy to integrate into vehicles. The system was proven effective in identifying the electrochemical properties of batteries under various operating conditions, including different temperatures and SOC levels.
Professor Kyeongha Kwon (the corresponding author) explained, “This system can be easily integrated into the battery management system (BMS) of electric vehicles and has demonstrated high measurement accuracy while significantly reducing the cost and complexity compared to traditional high-current EIS methods. It can contribute to battery diagnosis and performance improvements not only for electric vehicles but also for energy storage systems (ESS).”
This research, in which Young-Nam Lee, a doctoral student in the School of Electrical Engineering at KAIST participated as the first author, was published in the prestigious international journal IEEE Transactions on Industrial Electronics (top 2% in the field; IF 7.5) on September 5th. (Paper Title: Small-Perturbation Electrochemical Impedance Spectroscopy System With High Accuracy for High-Capacity Batteries in Electric Vehicles, Link: https://ieeexplore.ieee.org/document/10666864)
< Figure 2. Impedance measurement results of large-capacity batteries for electric vehicles. ZEW (commercial EW; MP10, Wonatech) versus ZMEAS (proposed system) >
This research was supported by the Basic Research Program of the National Research Foundation of Korea, the Next-Generation Intelligent Semiconductor Technology Development Program of the Korea Evaluation Institute of Industrial Technology, and the AI Semiconductor Graduate Program of the Institute of Information & Communications Technology Planning & Evaluation.
2024.10.17 View 1210 -
KAIST finds ways for Bacteria to produce PET-like materials
Among various eco-friendly polymers, polyhydroxyalkanoates (PHA) stand out for their excellent biodegradability and biocompatibility. They decompose naturally in soil and marine environments and are used in applications such as food packaging and medical products. However, natural PHA produced to date has faced challenges meeting various physical property requirements, such as durability and thermal stability, and has been limited in its commercial application due to low production concentrations. In light of this, KAIST researchers have recently developed a technology that could play a crucial role in solving the environmental pollution problem caused by plastics.
KAIST (represented by President Kwang-Hyung Lee) announced on August 26th that a research team led by Distinguished Professor Sang Yup Lee from the Department of Chemical and Biomolecular Engineering, including Dr. Youngjoon Lee and master's student Minju Kang, has successfully developed a microbial strain that efficiently produces aromatic polyester* using systems metabolic engineering.
※ Aromatic polyester: A polymer containing aromatic compounds (specific carbon ring structures like benzene) and ester bonds.
In this study, the research team used metabolic engineering to enhance the metabolic flux of the biosynthetic pathway for the aromatic monomer phenyllactate (PhLA) in E. coli. They manipulated the metabolic pathway to increase the polymer fraction accumulated within the cells and employed computer simulations to predict the structure of PHA synthase and improve the enzyme based on the structure-function relationship.
Through subsequent fermentation optimization, the team achieved the world’s highest concentration (12.3±0.1 g/L) for the efficient production of poly (PhLA) and successfully produced polyester through a 30L scale fed-batch fermentation, demonstrating the possibility of industrial-level production. The produced aromatic polyesters showed enhanced thermal properties, improved mechanical properties, and potential for use as drug delivery carriers.
< Figure 1. Development schematics of aromatic polyester producing microorganisms >
The research team also demonstrated that an exogenous phasin protein* plays a crucial role in increasing the intracellular polymer accumulation fraction, which is directly related to the economic feasibility and efficiency of non-natural PHA production. They improved PHA synthase using a rational enzyme design approach, predicting the three-dimensional structure of the enzyme through homology modeling (a method of predicting the three-dimensional structure of a new protein based on the structure of similar proteins) followed by molecular docking simulations (simulations that predict how well a monomer can bind to an enzyme) and molecular dynamics simulations (simulations that predict how molecules move and interact over time) to upgrade the enzyme into a mutant enzyme with enhanced monomer polymerization efficiency.
※ Exogenous phasin protein: Phasin is a protein related to PHA production, interacting with the cytoplasmic environment on the surface of granules of PHA, and playing a role in polymer accumulation and controlling the number and size of granules. In this study, genes encoding phasin proteins derived from various natural PHA-producing microorganisms were selected and introduced.
Dr. Youngjoon Lee, co-first author of the paper, explained, "The significance of this study lies in the fact that we have achieved the world's highest concentration of microbial-based aromatic polyester production using eco-friendly materials and methods. This technology is expected to play a crucial role in addressing the environmental pollution caused by plastics." Distinguished Professor Sang Yup Lee added, "This study, which presents various strategies for the high-efficiency production of useful polymers via systems metabolic engineering, is expected to make a significant contribution to solving climate change issues, particularly the recent plastic problem."
< Figure 2. Detailed development strategy for aromatic polyester producing microorganisms >
The research findings were published on August 21st in Trends in Biotechnology, published by Cell, an international academic journal.
※ Paper Title: “Microbial production of an aromatic homopolyester”
※ Author Information: Youngjoon Lee (KAIST, co-first author), Minju Kang (KAIST, co-first author), Woo Dae Jang (KAIST, second author), So Young Choi (KAIST, third author), Jung Eun Yang (KAIST, fourth author), Sang Yup Lee (KAIST, corresponding author), totaling six authors.
This research was supported by the "Development of Next-Generation Biorefinery Platform Technologies for Leading the Bio-based Chemicals Industry" project led by Distinguished Professor Sang Yup Lee at KAIST, under the eco-friendly chemical technology development project aimed at substituting petroleum, funded by the Ministry of Science and ICT. It was also supported by the "Development of Platform Technology for the Production of Novel Aromatic Bioplastic Using Microbial Cell Factories" project (Project Leader: Si Jae Park, Ewha Woman’s University).
2024.08.28 View 1856 -
KAIST Develops Microbial Liquid Egg Substitute
A team of researchers published a paper on developing a substitute for eggs using microorganisms, grabbing international attention. It is expected that the development of egg substitutes using non-animal raw materials will solve the problems of factory farming, which causes problems like increased emission of greenhouse gas and waste, and contribute to building a sustainable food system that allows easy protein intake.
KAIST (President Kwang-Hyung Lee) announced that Research Professor Kyeong Rok Choi from the Biological Process Research Center and Distinguished Professor Sang Yup Lee from the Department of Chemical and Biomolecular Engineering have published a paper on the development of an "Eco-Friendly Liquid Egg Substitute Derived from Microorganisms."
Eggs play a crucial role in various culinary applications due to their unique physicochemical properties such as gelling, foaming, and emulsifying, while also providing essential nutrients. However, traditional egg production is not only unethical and resource-intensive but also has significant environmental impacts such as greenhouse gas emissions and waste issues. Additionally, factors such as wars and trade regulations have led to significant increases in egg prices, highlighting food security concerns. In response to these issues, there has been growing interest in egg substitutes made from non-animal sources to establish a sustainable food system.
Although there has been progress in developing non-animal protein-based egg substitutes, no substitute has been able to fully replicate the essential functional properties of liquid eggs, such as gelling and foaming, while also providing complete nutrition. In this context, the research team aimed to develop a liquid egg substitute using microbial biomass, which has a protein content comparable to that of meat per unit dry mass. Various microorganisms, such as yeast, Bacillus, lactic acid bacteria, and other probiotics, have been proven safe through long-term human consumption. Microbial biomass requires fewer resources like water and land during production, and possesses high-quality nutrients, making it a promising sustainable food resource.
< Figure 1. Comparison of heat treatment results of microbial pellets and microbial lysates >
However, the semi-solid microbial biomass recovered through microbial cultivation was observed to turn liquid upon heating, unlike liquid egg. To address this, the research team devised a microbial lysate by breaking down the cell walls and cell membranes of microorganisms, which correspond to the eggshell. They found that the microbial lysate's proteins coagulated when heated and formed a gel similar to that of liquid egg. The gel formed from the heated microbial lysate was found to have microscopic structures and physical properties similar to those of boiled eggs. The addition of microbial-derived edible enzymes or plant-based materials allowed for the adjustment of its properties, enabling the creation of various textures.
Furthermore, the researchers demonstrated that the microbial lysate could form stable foams widely used in baking, such as meringues (made from egg whites). They successfully baked meringue cookies using this lysate, showing its potential as a functional liquid egg substitute.
Distinguished Professor Sang Yup Lee stated, "This substitute has excellent nutritional components, making it suitable for regular food consumption. It is especially promising as emergency food for long-term space travel, wartime situations, and other emergencies. More importantly, it contributes to securing a sustainable food system."
< Figure 2. Example of foaming ability of microbial lysate and meringue cookie production >
< Figure 3. Example of foaming ability of microbial lysate and meringue cookie production >
The paper was published online in the journal npj Science of Food, issued by Nature.
- Paper Title: Microbial lysates repurposed as liquid egg substitutes
- Authors: Kyeong Rok Choi (first author), Da-Hee Ahn, Seok Yeong Jung, YuHyun Lee, and Sang Yup Lee (corresponding author)
This research was supported by the Ministry of Science and ICT's project for developing eco-friendly chemical technologies to replace petroleum (Project Leader: Distinguished Professor Sang Yup Lee, KAIST) and the Rural Development Administration's Agricultural Microorganisms Project Group (Director: Professor Pan-sik Jang, Seoul National University) for developing protein production technology from inorganic substances through microbial metabolic system control (Project Leader: Research Professor Kyeong Rok Choi, KAIST).
2024.07.05 View 3277 -
KAIST and Merck Sign MOU to Boost Biotech Innovation
< (From left) KAIST President Kwang-Hyung Lee and Merck CEO Matthias Heinzel >
KAIST (President Kwang-Hyung Lee) signed a Memorandum of Understanding (MOU) with Merck Life Science (CEO Matthias Heinzel) on May 29 to foster innovation and technology creation in advanced biotechnology.
Since May of last year, the two institutions have been discussing multidimensional innovation programs and will now focus on industry-academia cooperation to tackle bioindustry challenges with this MOU as a foundation.
KAIST will conduct joint research projects in various advanced biotechnology fields, such as synthetic biology, mRNA, cell line engineering, and organoids, using the chemical and biological portfolios provided by Merck.
Additionally, KAIST will establish an Experience Lab in collaboration with the Department of Materials Science and Engineering and the Graduate School of Medical Science and Engineering. This lab will support the discovery and analysis of candidate substances in materials science and biology.
Programs to enhance researchers' capabilities will also be offered. Scholarships for graduate students and awards for professors will be implemented. Researchers will have opportunities to participate in global academic events and educational programs hosted by Merck, such as the Curious 2024 Future Insight Conference and the Innovation Cup.
M Ventures, a venture capital subsidiary of Merck Group, will collaborate with KAIST's startup institute to support technology commercialization and continue to develop their startup ecosystem.
The signing ceremony at KAIST's main campus in Daejeon was attended by the CEO of Merck Life Science and the President of KAIST along with representatives from both institutions.
Matthias Heinzel, a member of the Executive Board of Merck and CEO Life Science, said, “This agreement with KAIST is a significant step toward accelerating the development of the life science industry both in Korea and globally. Advancing life science research and fostering the next generation of scientists is essential for discovering new medicines to meet global health needs.”
President Kwang-Hyung Lee responded, “We are pleased to share a vision for scientific advancement with Merck, a leading global technology company. We anticipate that this partnership will strengthen the connection between Merck’s life science business and the global scientific community.”
In March, Merck, a global science and technology company with over 350 years of history, announced a plan to invest 430 billion KRW (€300 million) to build a bioprocessing center in Daejeon, where KAIST is located. This is Merck's largest investment in the Asia-Pacific region.
2024.05.30 View 2811 -
KAIST introduces microbial food as a strategy food production of the future
The global food crisis is increasing due to rapid population growth and declining food productivity to climate change. Moreover, today's food production and supply system emit a huge amount of carbon dioxide, reaching 30% of the total amount emitted by humanity, aggravating climate change. Sustainable and nutritious microbial food is attracting attention as a key to overcoming this impasse.
KAIST (President Kwang Hyung Lee) announced on April 12th that Research Professor Kyeong Rok Choi of the BioProcess Engineering Research Center and Distinguished Professor Sang Yup Lee from the Department of Chemical and Biomolecular Engineering published a paper that proposes a direction of research on ‘microbial food production from sustainable raw materials.’
Microbial food refers to various foods and food ingredients produced using microorganisms. Microbial biomass contains a large amount of protein per unit in dry mass, comparable to that of meat, and emits the smallest amount of carbon dioxide and is required to produce a unit mass compared to various livestock, fish, shellfish, and crops. Since the amount of water and space requirement is small, it can be an eco-friendly, sustainable and highly nutritious food resource.
Fermented foods are the most readily available microbial foods around us. Although the proportion of microbial biomass in fermented foods is small, compounds with relatively low nutritional value, such as carbohydrates, are consumed during the fermentation process, and as microorganisms proliferate, the content of nutrients with higher nutritional value, such as proteins and vitamins, increases.
Various food compounds isolated and purified from biomass or culture media obtained through microbial culture are also a branch of microbial food. Examples that can be found around us include various amino acids, including monosodium glutamate, food proteins, enzymes, flavoring compounds, food colorings, and bioactive substances.
< Figure 1. Schematic diagram portraying various microbial biomass production strategies utlizing sustainable feedstocks >
Lastly, the most ultimate and fundamental form of microbial food can be said to be microbial biomass or extracts produced through microbial culture and foods cooked using them. A representative example is single-cell protein, which collectively refers to microbial biomass or microbial proteins extracted from it.
In this paper, the researchers comprehensively covered various non-edible raw materials and strategies for using them that can be used to produce microbial food in a more sustainable way. Furthermore, it covers various microbial foods that are actually produced in the industry using the relevant raw materials and their characteristics, as well as prospects for the production and generalization of sustainable microbial foods.
Research Professor Kyeong Rok Choi, the first author of this paper, said, “Microbial foods produced from various sustainable raw materials will soon be commonly encountered at our tables.” Second author Seok Yeong Jung, a doctoral student, also said, “Microbial foods of the future will not be limited foods consumed only out of a sense of obligation to the environment, but will be complete foods that are consumed by choice because of their nutritional value and taste.” In addition, Distinguished Professor Sang Yup Lee said, “It is time for the industry and academia, as well as the public and private sectors, to cooperate more closely so that more diverse microbial foods can be developed and supplied in order to create a sustainable society for ourselves and our descendants.”
< Figure 2. Compositions and environmental footprints of animal, plant and microbial biomass. >
This paper was published online on April 9 in ‘Nature Microbiology’ published by Nature.
※ Paper title: From sustainable feedstocks to microbial foods
※ Author information: Kyeong Rok Choi (first author), Seok Yeong Jung (second author) and Sang Yup Lee (corresponding author)
This research was conducted under the development of platform technologies of microbial cell factories for the next-generation biorefineries project (project leader KAIST Distinguished Professor Sang Yup Lee) supported by the Ministry of Science and ICT and the Cooperative Research Program for Agriculture Science and Technology Development (Project leader KAIST Research Professor Kyeong Rok Choi) of the Agricultural Microbiology Project Group (Director, Professor Pahn-Shick Chang) supported by the Rural Development Administration.
2024.04.12 View 3789 -
KAIST Develops Healthcare Device Tracking Chronic Diabetic Wounds
A KAIST research team has developed an effective wireless system that monitors the wound healing process by tracking the spatiotemporal temperature changes and heat transfer characteristics of damaged areas such as diabetic wounds.
On the 5th of March, KAIST (represented by President Kwang Hyung Lee) announced that the research team led by Professor Kyeongha Kwon from KAIST’s School of Electrical Engineering, in association with Chung-Ang University professor Hanjun Ryu, developed digital healthcare technology that tracks the wound healing process in real time, which allows appropriate treatments to be administered.
< Figure 1. Schematic illustrations and diagrams of real-time wound monitoring systems. >
The skin serves as a barrier protecting the body from harmful substances, therefore damage to the skin may cause severe health risks to patients in need of intensive care. Especially in the case of diabetic patients, chronic wounds are easily formed due to complications in normal blood circulation and the wound healing process. In the United States alone, hundreds of billions of dollars of medical costs stem from regenerating the skin from such wounds. While various methods exist to promote wound healing, personalized management is essential depending on the condition of each patient's wounds.
Accordingly, the research team tracked the heating response within the wound by utilizing the differences in temperature between the damaged area and the surrounding healthy skin. They then measured heat transfer characteristics to observe moisture changes near the skin surface, ultimately establishing a basis for understanding the formation process of scar tissue. The team conducted experiments using diabetic mice models regarding the delay in wound healing under pathological conditions, and it was demonstrated that the collected data accurately tracks the wound healing process and the formation of scar tissue.
To minimize the tissue damage that may occur in the process of removing the tracking device after healing, the system integrates biodegradable sensor modules capable of natural decomposition within the body. These biodegradable modules disintegrate within the body after use, thus reducing the risk of additional discomfort or tissue damage upon device removal. Furthermore, the device could one day be used for monitoring inside the wound area as there is no need for removal.
Professor Kyeongha Kwon, who led the research, anticipates that continuous monitoring of wound temperature and heat transfer characteristics will enable medical professionals to more accurately assess the status of diabetic patients' wounds and provide appropriate treatment. He further predicted that the implementation of biodegradable sensors allows for the safe decomposition of the device after wound healing without the need for removal, making live monitoring possible not only in hospitals but also at home.
The research team plans to integrate antimicrobial materials into this device, aiming to expand its technological capabilities to enable the observation and prevention of inflammatory responses, bacterial infections, and other complications. The goal is to provide a multi-purpose wound monitoring platform capable of real-time antimicrobial monitoring in hospitals or homes by detecting changes in temperature and heat transfer characteristics indicative of infection levels.
< Image 1. Image of the bioresorbable temperature sensor >
The results of this study were published on February 19th in the international journal Advanced Healthcare Materials and selected as the inside back cover article, titled "Materials and Device Designs for Wireless Monitoring of Temperature and Thermal Transport Properties of Wound Beds during Healing."
This research was conducted with support from the Basic Research Program, the Regional Innovation Center Program, and the BK21 Program.
2024.03.11 View 3383 -
KAIST Research Team Creates the Scent of Jasmine from Microorganisms
The fragrance of jasmine and ylang-ylang, used widely in the manufacturing of cosmetics, foods, and beverages, can be produced by direct extraction from their respective flowers. In reality, this makes it difficult for production to meet demand, so companies use benzyl acetate, a major aromatic component of the two fragrances that is chemically synthesized from raw materials derived from petroleum.
On February 26, a KAIST research team led by Research Professor Kyeong Rok Choi from the BioProcess Engineering Research Center and Distinguished Professor Sang Yup Lee from the Department of Chemical and Biomolecular Engineering revealed the development of the first microbial process to effectively produce benzyl acetate, an industrially useful compound, from renewable carbon sources such as glucose. The results were published in their paper titled “A microbial process for the production of benzyl acetate”.
< Figure 1. Production of benzyl acetate through co-culture of upstream and downstream strains harboring the benzoic acid-dependent pathway. >
The team, led by Distinguished Professor Lee, aimed to produce benzyl acetate through an environmentally friendly and sustainable method, and developed an Escherichia coli strand to convert glucose into benzyl acetate through system metabolic engineering*.
*System metabolic engineering: a field of research founded by Distinguished Professor Lee to effectively develop microbial cell plants, a core component of the bio-industry that will replace the existing chemical industry, which is highly dependent on petroleum.
The research team developed a metabolic pathway that biosynthesizes benzyl acetate from benzoic acid derived from glucose, and successfully produced benzyl acetate by co-culturing** the strain.
**co-culture: simultaneously synthesizing two or more types of microorganisms in a mixture
However, it has been confirmed that the enzyme used to convert benzoic acid into benzyl acetate in this co-culturing technique acts non-specifically on an intermediate product during benzoic acid biosynthesis, producing a by-product called cinnamyl acetate. This process consumes the intermediate product needed for benzoic acid biosynthesis, thereby reducing the production efficiency of the target compound, benzyl acetate.
To overcome this problem, Distinguished Professor Lee and his team devised a delayed co-culture method, where they first produced benzoic acid in the earlier stages of fermentation by only culturing the top strain that produces benzoic acid from glucose, and later inoculated the bottom strain to convert the accumulated benzoic acid in the culture medium into benzyl acetate.
By applying this co-culture technique, the team suppressed the formation of by-products without further strain improvement or applying additional enzymes, and multiplied the concentration of the target compound by 10 times, producing 2.2 g/L of benzyl acetate. In addition, the team confirmed its potential for the commercial production of benzyl acetate through a technical economic analysis on this microbial process.
< Figure 2. Delayed co-culture of the Bn1 and Bn-BnAc3 strains for improved production of benzyl acetate through the benzoic acid-independent pathway.>
Research Professor Keyong Rok Choi, who was the first author of this paper, said, “This work is significant in that we have developed an effective microbial process to produce the industrially useful compound benzyl acetate, and also in that we have suggested a new approach to overcome the target chemical efficiency diminution and by-product formation issues caused commonly through non-specific enzyme activities during metabolic engineering.”
Distinguished Professor Lee said, “If we can increase the variety and number of microbial processes that produce useful chemicals through sustainable methods and at the same time develop effective strategies to solve chronic and inevitable problems that arise during microbial strain development, we will be able to accelerate the transition from the petrochemical industry into the eco-friendly and sustainable bio-industry.
This work was published online in Nature Chemical Engineering, issued by Nature.
This research was supported by the ‘Implementation of Intelligent Cell Factory Technology (PI: Distinguished Professor Sang Yup Lee) Project by the Ministry of Science and ICT, and the ‘Development of Protein Production Technology from Inorganic Substances through Microbiological Metabolic System Control’ (PI: Research Professor Kyeong Rok Choi) by the Agricultural Microbiological Project Group at the Rural Development Administration.
2024.03.05 View 3444 -
KAIST to begin Joint Research to Develop Next-Generation LiDAR System with Hyundai Motor Group
< (From left) Jong-Soo Lee, Executive Vice President at Hyundai Motor, Sang-Yup Lee, Senior Vice President for Research at KAIST >
The ‘Hyundai Motor Group-KAIST On-Chip LiDAR Joint Research Lab’ was opened at KAIST’s main campus in Daejeon to develop LiDAR sensors for advanced autonomous vehicles.
The joint research lab aims to develop high-performance and compact on-chip sensors and new signal detection technology, which are essential in the increasingly competitive autonomous driving market. On-chip sensors, which utilize semiconductor manufacturing technology to add various functions, can reduce the size of LiDAR systems compared to conventional methods and secure price competitiveness through mass production using semiconductor fabrication processes.
The joint research lab will consist of about 30 researchers, including the Hyundai-Kia Institute of Advanced Technology Development research team and KAIST professors Sanghyeon Kim, Sangsik Kim, Wanyeong Jung, and Hamza Kurt from KAIST’s School of Electrical Engineering, and will operate for four years until 2028.
KAIST will be leading the specialized work of each research team, such as for the development of silicon optoelectronic on-chip LiDAR components, the fabrication of high-speed, high-power integrated circuits to run the LiDAR systems, and the optimization and verification of LiDAR systems.
Hyundai Motor and Kia, together with Hyundai NGV, a specialized industry-academia cooperation institution, will oversee the operation of the joint research lab and provide support such as monitoring technological trends, suggesting research directions, deriving core ideas, and recommending technologies and experts to enhance research capabilities.
A Hyundai Motor Group official said, "We believe that this cooperation between Hyundai Motor Company and Kia, the leader in autonomous driving technology, and KAIST, the home of world-class technology, will hasten the achievement of fully autonomous driving." He added, "We will do our best to enable the lab to produce tangible results.”
Professor Sanghyeon Kim said, "The LiDAR sensor, which serves as the eyes of a car, is a core technology for future autonomous vehicle development that is essential for automobile companies to internalize."
2024.02.27 View 4379 -
A Korean research team develops a new clinical candidate for fatty liver disease
A team of Korean researchers have succeeded in developing a new drug candidate for the treatment of non-alcoholic fatty liver disease (NAFLD) acting on peripheral tissues. To date, there has not been an optimal treatment for non-alcoholic steatohepatitis (NASH), and this discovery is expected to set the grounds for the development of new drugs that can safely suppress both liver fat accumulation and liver fibrosis at the same time.
A joint research team led by Professor Jin Hee Ahn from Gwangju Institute of Science and Technology (GIST) and Professor Hail Kim from the KAIST Graduate School of Medical Science and Engineering developed a new chemical that can suppress disease-specific protein (HTR2A) through years of basic research. The team also revealed to have verified its efficacy and safety through preclinical tests (animal tests) at JD Bioscience Inc., a start-up company founded by Professor Ahn.
Although NAFLD has a prevalence rate as high as 20-30%, and about 5% of the global adult population suffers from NASH, there are no commercial drugs targeting them to date. NAFLD is a chronic disease that starts from the fatty liver and progresses into steatohepatitis, fibrosis, cirrhosis, and liver cancer. The mortality rate of patients increases with accompanied cardiovascular diseases and liver-related complications, and appropriate treatment in the early stage is hence necessary.
< Figure 1. Strategy and history of 5HT2A antagonists. Library and rational design for the development of compound 11c as a potent 5HT2A antagonist. Previous research efforts were discontinued due to limited oral absorption and safety. A therapeutic candidate to overcome this problem was identified and phase 1 clinical trials are currently in progress. >
The new synthetic chemical developed by the joint GIST-KAIST research is an innovative drug candidate that shows therapeutic effects on NASH based on a dual action mechanism that inhibits the accumulation of fat in the liver and liver fibrosis by suppressing the serotonin receptor protein 5HT2A.
The research team confirmed its therapeutic effects in animal models for NAFLD and NASH, in which hepatic steatosis and liver fibrosis* caused by fat accumulation in the liver were suppressed simultaneously by 50-70%.
*fibrosis: stiffening of parts of the liver, also used as a major indicator to track the prognosis of steatosis
The research team explained that the material was designed with optimal polarity and lipid affinity to minimize its permeability across the blood-brain barrier. It therefore does not affect the brain, and causes little side effects in the central nervous system (CNS) such as depression and suicidal ideations, while demonstrating excellent inhibition on its target protein present in tissues outside brain (IC50* = 14 nM). The team also demonstrated its superior efficacy in improving liver fibrosis when compared to similar drugs in the phase 3 clinical trial.
*IC50 (half maximal inhibitory concentration): the concentration at which a chemical suppresses 50% of a particular biological function
< Figure 2. GM-60106 (11c)'s effect on obesity: When GM-60106 was administered to an obese animal model (mice) for 2 months, body weight, body fat mass, and blood sugar were significantly reduced (a-d). In addition, the steatohepatitis level (NAFLD Activity Score) and the expression of genes of the treated mice involved in adipogenesis along with blood/liver fat decreased (e-h) >
Based on the pharmacological data obtained through preclinical trials, the team evaluated the effects of the drug on 88 healthy adults as part of their phase 1 clinical trial, where the side effects and the safe dosage of a drug are tested against healthy adults. Results showed no serious side effects and a good level of drug safety.
In addition, a preliminary efficacy evaluation on eight adults with steatohepatitis is currently underway.
Professor Jin Hee Ahn said, “The aim of this research is to develop a treatment for NASH with little side effects and guaranteed safety by developing a new target. The developed chemical is currently going through phase 1 of the global clinical trial in Australia through JD Bioscience Inc., a bio venture company for innovative drug development.” he added, “The candidate material the research team is currently developing shows not only a high level of safety and preventative effects by suppressing fat accumulation in the liver, but also a direct therapeutic effect on liver fibrosis. This is a strength that distinguishes our material from other competing drugs.”
< Figure 3. Efficacy of GM-60106 (11c) on liver fibrosis: When GM-60106 was administered to a steatohepatitis model (mice) for 3 months, the expression of genes associated with tissue fibrosis was significantly reduced (b-c). As a result of a detailed analysis of the tissues of the animal model, it was confirmed that the rate of tissue fibrosis was reduced and the expression rate of genes related to tissue fibrosis and inflammation was also significantly reduced (e-h). >
Professor Hail Kim from KAIST said, “Until now, this disease did not have a method of treatment other than weight control, and there has been no attempt to develop a drug that can be used for non-obese patients.” He added, “Through this research, we look forward to the development of various treatment techniques targeting a range of metabolic diseases including NASH that do not affect the weight of the patient.”
This study, conducted together by the research teams led by Professor Ahn from GIST and Professor Kim from KAIST, as well as the research team from JD Bioscience Inc., was supported by the Ministry of Science and ICT, and the National New Drug Development Project. The results of this research were published by Nature Communications on January 20.
The team also presented the results of their clinical study on the candidate material coded GM-60106 targeting metabolic abnormality-related MASH* at NASH-TAG Conference 2024, which was held in Utah for three days starting on January 4, which was selected as an excellent abstract.
*MASH (Metabolic Dysfunction-Associated Steatohepatitis): new replacement term for NASH
2024.02.21 View 4551 -
KAIST Research Team Develops Sweat-Resistant Wearable Robot Sensor
New electromyography (EMG) sensor technology that allows the long-term stable control of wearable robots and is not affected by the wearer’s sweat and dead skin has gained attention recently. Wearable robots are devices used across a variety of rehabilitation treatments for the elderly and patients recovering from stroke or trauma.
A joint research team led by Professor Jae-Woong Jung from the KAIST School of Electrical Engineering (EE) and Professor Jung Kim from the KAIST Department of Mechanical Engineering (ME) announced on January 23rd that they have successfully developed a stretchable and adhesive microneedle sensor that can electrically sense physiological signals at a high level without being affected by the state of the user’s skin.
For wearable robots to recognize the intentions behind human movement for their use in rehabilitation treatment, they require a wearable electrophysiological sensor that gives precise EMG measurements. However, existing sensors often show deteriorating signal quality over time and are greatly affected by the user’s skin conditions. Furthermore, the sensor’s higher mechanical hardness causes noise since the contact surface is unable to keep up with the deformation of the skin. These shortcomings limit the reliable, long-term control of wearable robots.
< Figure 1. Design and working concept of the Stretchable microNeedle Adhesive Patch (SNAP). (A) Schematic illustration showing the overall system configuration and application of SNAP. (B) Exploded view schematic diagram of a SNAP, consisting of stretchable serpentine interconnects, Au-coated Si microneedle, and ECA made of Ag flakes–silicone composite. (C) Optical images showing high mechanical compliance of SNAP. >
However, the recently developed technology is expected to allow long-term and high-quality EMG measurements as it uses a stretchable and adhesive conducting substrate integrated with microneedle arrays that can easily penetrate the stratum corneum without causing discomfort. Through its excellent performance, the sensor is anticipated to be able to stably control wearable robots over a long period of time regardless of the wearer’s changing skin conditions and without the need for a preparation step that removes sweat and dead cells from the surface of their skin.
The research team created a stretchable and adhesive microneedle sensor by integrating microneedles into a soft silicon polymer substrate. The hard microneedles penetrate through the stratum corneum, which has high electrical resistance. As a result, the sensor can effectively lower contact resistance with the skin and obtain high-quality electrophysiological signals regardless of contamination. At the same time, the soft and adhesive conducting substrate can adapt to the skin’s surface that stretches with the wearer’s movement, providing a comfortable fit and minimizing noise caused by movement.
< Figure 2. Demonstration of the wireless Stretchable microNeedle Adhesive Patch (SNAP) system as an Human-machine interfaces (HMI) for closed-loop control of an exoskeleton robot. (A) Illustration depicting the system architecture and control strategy of an exoskeleton robot. (B) The hardware configuration of the pneumatic back support exoskeleton system. (C) Comparison of root mean square (RMS) of electromyography (EMG) with and without robotic assistance of pretreated skin and non-pretreated skin. >
To verify the usability of the new patch, the research team conducted a motion assistance experiment using a wearable robot. They attached the microneedle patch on a user’s leg, where it could sense the electrical signals generated by the muscle. The sensor then sent the detected intention to a wearable robot, allowing the robot to help the wearer lift a heavy object more easily.
Professor Jae-Woong Jung, who led the research, said, “The developed stretchable and adhesive microneedle sensor can stability detect EMG signals without being affected by the state of a user’s skin. Through this, we will be able to control wearable robots with higher precision and stability, which will help the rehabilitation of patients who use robots.”
The results of this research, written by co-first authors Heesoo Kim and Juhyun Lee, who are both Ph.D. candidates in the KAIST School of EE, were published in Science Advances on January 17th under the title “Skin-preparation-free, stretchable microneedle adhesive patches for reliable electrophysiological sensing and exoskeleton robot control”.
This research was supported by the Bio-signal Sensor Integrated Technology Development Project by the National Research Foundation of Korea, the Electronic Medicinal Technology Development Project, and the Step 4 BK21 Project.
2024.01.30 View 4076 -
KAIST presents strategies for environmentally friendly and sustainable polyamides production
- Provides current research trends in bio-based polyamide production
- Research on bio-based polyamides production gains importance for achieving a carbon-neutral society
Global industries focused on carbon neutrality, under the slogan "Net-Zero," are gaining increasing attention. In particular, research on microbial production of polymers, replacing traditional chemical methods with biological approaches, is actively progressing.
Polyamides, represented by nylon, are linear polymers widely used in various industries such as automotive, electronics, textiles, and medical fields. They possess beneficial properties such as high tensile strength, electrical insulation, heat resistance, wear resistance, and biocompatibility. Since the commercialization of nylon in 1938, approximately 7 million tons of polyamides are produced worldwide annually. Considering their broad applications and significance, producing polyamides through bio-based methods holds considerable environmental and industrial importance.
KAIST (President Kwang-Hyung Lee) announced that a research team led by Distinguished Professor Sang Yup Lee, including Dr. Jong An Lee and doctoral candidate Ji Yeon Kim from the Department of Chemical and Biomolecular Engineering, published a paper titled "Current Advancements in Bio-Based Production of Polyamides”. The paper was featured on the cover of the monthly issue of "Trends in Chemistry” by Cell Press.
As part of climate change response technologies, bio-refineries involve using biotechnological and chemical methods to produce industrially important chemicals and biofuels from renewable biomass without relying on fossil resources. Notably, systems metabolic engineering, pioneered by KAIST's Distinguished Professor Sang Yup Lee, is a research field that effectively manipulates microbial metabolic pathways to produce valuable chemicals, forming the core technology for bio-refineries. The research team has successfully developed high-performance strains producing a variety of compounds, including succinic acid, biodegradable plastics, biofuels, and natural products, using systems metabolic engineering tools and strategies.
The research team predicted that if bio-based polyamide production technology, which is widely used in the production of clothing and textiles, becomes widespread, it will attract attention as a future technology that can respond to the climate crisis due to its environment-friendly production technology. In this study, the research team comprehensively reviewed the bio-based polyamide production strategies. They provided insights into the advancements in polyamide monomer production using metabolically engineered microorganisms and highlighted the recent trends in bio-based polyamide advancements utilizing these monomers. Additionally, they reviewed the strategies for synthesizing bio-based polyamides through chemical conversion of natural oils and discussed the biodegradability and recycling of the polyamides. Furthermore, the paper presented the future direction in which metabolic engineering can be applied for the bio-based polyamide production, contributing to environmentally friendly and sustainable society.
Ji Yeon Kim, the co-first author of this paper from KAIST, stated "The importance of utilizing systems metabolic engineering tools and strategies for bio-based polyamides production is becoming increasingly prominent in achieving carbon neutrality."
Professor Sang Yup Lee emphasized, "Amid growing concerns about climate change, the significance of environmentally friendly and sustainable industrial development is greater than ever. Systems metabolic engineering is expected to have a significant impact not only on the chemical industry but also in various fields."
< [Figure 1] A schematic overview of the overall process for polyamides production >
This paper by Dr. Jong An Lee, PhD student Ji Yeon Kim, Dr. Jung Ho Ahn, and Master Yeah-Ji Ahn from the Department of Chemical and Biomolecular Engineering at KAIST was published in the December issue of 'Trends in Chemistry', an authoritative review journal in the field of chemistry published by Cell. It was published on December 7 as the cover paper and featured review.
※ Paper title: Current advancements in the bio-based production of polyamides
※ Author information: Jong An Lee, Ji Yeon Kim, Jung Ho Ahn, Yeah-Ji Ahn, and Sang Yup Lee
This research was conducted with the support from the development of platform technologies of microbial cell factories for the next-generation biorefineries project and C1 gas refinery program by Korean Ministry of Science and ICT.
< [Figure 2] Cover paper of the December issue of Trends in Chemistry >
2023.12.21 View 3746