User Interview – Dr. Takashi Endo, National Institute of Advanced Industrial Science and Technology

The following describes an interview with Dr. Takashi Endo, Group Leader of AIST, one of the world’s top experts on cellulose nanofibers.

1. You installed THINKY MIXER ARE-310 in 2012, and then another of the same model. What was the reason for this additional installation?

Because it is frequently used, has a reasonable price, and is very user-friendly.

2. How did you first learn about THINKY MIXER?

I was performing research in collaboration with an automobile parts company. One of the managers of the company recommended THINKY MIXER for mixing rubber slurry, etc. At that time, I did not know of the existence of THINKY MIXER.

3. Were you satisfied after using it?

The research always involves a process of mixing fibrous materials like cellulose. When cellulose is mixed with rubber or resin using equipment such as a stirrer with blades, it becomes lumpy and foamy, which is very troublesome. Therefore, I tried to disperse it using an ultrasonic homogenizer and various other methods. At that time, THINKY MIXER was recommended and provided really satisfactory results.

4. Both problems of clean mixing and foam removal were solved at the same time. Now, you seem to be recommending the machine to other researchers.

Some of researchers performing joint research with us have installed THINKY MIXER in their own laboratories after using the machine here.

5. By the way, I saw some shoes at the display corner in the corridor. Is cellulose nanofiber (CNF) used in rubber soles?

They are sports shoes. Their weight has been reduced by adding CNF to the rubber of the shoe sole. The master batch was made using THINKY MIXER.
THINKY MIXER is also used to mix CNF into resin powder. One of the research subjects is to reinforce rubber or plastic with CNF. CNF is dissolved by heating after being uniformly dispersed in resin powder.
The Japanese government has provided a budget of ten billion yen for research on resin reinforcement. The body of automobiles is currently being considered one of the focal subjects by the government. We are working on different perspectives such as interior materials and shoes.

6. What prompted you to start researching CNF?

Because my hometown is in Yamaguchi Prefecture close to Hiroshima, I attended Hiroshima University until I received my doctoral degree there. The subject of my doctoral thesis at the university was how fragrance ingredients are biosynthesized in plants. After that, I started working for the Agency of Industrial Science and Technology, the predecessor of AIST, and was assigned to the paper pulp laboratory of Government Industrial Research Institute, Shikoku (Takamatsu City, Kagawa Prefecture). There, following the instruction of my boss, I decided to work on making a fine powder of cellulose.
Because it was not very interesting just to make powder, I wondered what would happen if I put resin in it. This was the start of my research on the composite material of cellulose and resin. The CNF that I am currently studying is ultimately fine, but the actual experiments I am doing are essentially the same as those at that time. Originally, cellulose was not my specialty and therefore, I initially spent a lot of time studying it. To be honest, the first year was very hard for me. I thought that I had worked on a rather “refined” subject at university, but now I had to work on an “unrefined” subject. Therefore, I even thought of quitting the research.
In the second year, I roused myself and decided to study under Dr. Akira Isogai at the University of Tokyo for a short period of time. That was 24 years ago. Dr. Isogai was still a research associate at ….
The benefit of staying at the University of Tokyo was expanding the range of acquaintances rather than the actual research I did there. While I was conducting experiments, the professor there often invited me out, saying “Let’s go see a movie now” or “Let’s go out for a drink” (laugh). I think that the numerous acquaintances I acquired at the University of Tokyo at that time, including famous professors and young professors and researchers working in the field of cellulose, turned out to be quite useful.
Ten years ago, I moved from Takamatsu to Hiroshima. At that time, bioethanol was one of the hot topics. Therefore, we also conducted research on it, acquiring a budget from NEDO (New Energy and Industrial Technology Development Organization). By adopting the method of improving the enzymatic degradability by finely shredding wood to increase their surface area (the hydrothermal and mechanochemical treatment technology), which was originally developed by AIST, we were able to achieve a very good result. I think that it was probably the lowest cost method that outclassed others.
While being involved with bioethanol and nanofibers, I have worked on materials research including composite materials throughout my career. The basis of my research is to “pulverize and create fine particles of materials”. Three years ago, I received an academic award. As I talked during the award lecture, I was proud of the fact that I kept on with the research on the same subject without hesitation for 25 years. The object is “cellulose” and the method is “pulverization”. This has continued up to now for 25 years. Perhaps it was possible because enough research funds were available and, of course, thanks to many colleagues.

7. Please tell us the prospects of future research.

Our group concept this year is the “development of technology appealing to the five senses”. Reinforced plastic may be sufficient as an outcome. However, rather than setting the strength of plastics as the primary target, we are performing research and development of plastics emphasizing the “appearance” such as “color” and “design quality”. Even if a manufacturer promotes the good quality of a product such as “very high strength”, the buyer may choose a product based on “design and looks”, saying “it is more beautiful”, etc. For example, when we buy a cup, even if it says “no damage even in a dishwasher”, most of us will not choose it if there is another with a more appealing design. The appearance is a very important factor in determining the attractiveness of products. In addition to the appearance, we are working on research and development considering the five senses such as touch, aroma, and sound quality, etc. Now, I am performing joint research with a laboratory of a food company. Therefore, “taste”, one of the five senses, is also important.
Another concept of the group is to “attain sufficient performance with thicker nanofibers”. Thicker nanofibers can be synthesized at a lower price. Currently, the price remains high because people prefer thinness, such as a few nm to 10 nm. If we can demonstrate that sufficient performance can be achieved even with fibers of micron or submicron sizes, the price will go down and the materials are likely to become more popular. When I state this opinion to people in private companies, they usually say “that really opened my eyes”.
The motto of AIST is “to bring technology into society”. It is my favorite concept. I think, unlike in universities, it is necessary to develop technology useful in society. I always conduct research considering whether it can really be industrialized.

Dr. Endo and Dr. Kumagai in the laboratory

There is lots of equipment in the laboratory. Collaborating researchers come here to carry out experiments. Sometimes, dozens of people stay in the room at a time making it very crowded. Currently, the group is collaborating with about 20 companies.

Research on orange juice is performed in collaboration with Ehime Prefecture. By extracting CNF from orange waste and adding it to the juice, the orange juice becomes well dispersed and free of precipitation. When precipitation occurs, it may give the impression that the juice has become stale. The research aim is to prevent this precipitation. The juice produced by the above method looks very impressive.

Nata de coco and chia seeds, which are attracting attention as superfoods, are also actually cellulose. Therefore, cellulose is something very familiar to people.

In addition, a cosmetic (solid foundation) made from cellulose has been developed. Because cellulose absorbs oil, it adsorbs sebum oil, preventing makeup from coming off and making pores in the skin inconspicuous. It is already on the market and is selling well both domestically and internationally.

There are many other products that were developed in the past or are currently being developed by Dr. Endo. I am looking forward to his success, as well as to future trends and development in the relevant industry.

Remarks after the interview

AIST Chugoku, relocated from Kure City to Higashi Hiroshima City in 2010, is in a very beautiful building. Dr. Endo gives a talk, as a volunteer, to children at the science club of Yamato Museum in Kure every year. He is very active in giving various lectures and actually gave a lecture every two weeks last year. When I visited his laboratory, he kindly told various anecdotes and then gave me a laboratory tour. Thank you very much, Dr. Endo.

Profile of Dr. Takashi Endo
Biography
1992: Completed Doctorate Course, Graduate School of Science, Hiroshima University [Doctor of Science]
1992: Joined Government Industrial Research Institute, Shikoku, Agency of Industrial Science and Technology, Ministry of International Trade and Industry (Takamatsu City, Kagawa Prefecture)
2001: Senior Researcher at AIST (National Institute of Advanced Industrial Science and Technology) (reorganization)
2005: Team Leader, Hydrothermal and Ingredient Separation Team, Biomass Technology Research Center, AIST (Kure City, Hiroshima Prefecture)
2012: Team Leader, Cellulose Utilization Team, Biomass Refinery Research Center, AIST (Higashi Hiroshima City, Hiroshima Prefecture)
2015: (up to now) Group Leader, Cellulose Materials Group, Research Institute for Sustainable Chemistry, AIST (reorganization)

Field of expertise
Cellulose chemistry, polymer chemistry, natural organic chemistry, wood chemistry

Research subjects
– Technology for forming fine particles of biomass such as cellulose
– Woody-biomass-type plastic composite molding material
– Enzymatic saccharification pretreatment for bioethanol production
– Technology of manufacturing and utilization of cellulose nanofibers

Awards
2000: Selected as the 59th Notable Invention Award, Science and Technology Agency
2001: Encouragement Award of Cellulose Society of Japan
2014: Cellulose Society of Japan Award

Academic Activities
Vice president of Nanocellulose Forum
President of Kansai Branch and Member of Board of Directors, Cellulose Society of Japan
Secretary of Chugoku-Shikoku Branch, Society of Polymer Science, Japan (until 2015)
Director, Chugoku-Shikoku Branch, Japan Wood Research Society
Member of Wood Science Committee, Japan Technical Association of the Pulp and Paper Industry
Member of Research Planning Committee, Wood and Plastic Composite Materials Division, Wood Technological Association of Japan