Activity report

Tomoko Shinomura, ProfessorDepartment of Biosciences Faculty of Science and Faculty of Science and Engineering,Teikyo University

Completed the master's program at the Graduate Graduate School Life Sciences, University of Tsukuba in 1983. Joined Hitachi, Ltd. in 1984 and was assigned to the Central Research Laboratory, where he has been engaged in various researches. In 2000, he was awarded a doctoral degree in science from the University of Tsukuba. In the latter half of the 2000s, he participated in research on the removal of microbes from the ballast water of ships, and then on the growth of Euglena. Since April 2010, he has been appointed to the Faculty of Science and Technology of Teikyo Faculty of Science and Engineering as a Professor in the Plant Molecular Cell Science Laboratory, Department of Biosciences.

Microalgae are microscopic-sized phytoplankton that generally inhabit water, such as Euglena (Euglena) and Pediastrum. These microalgae, which are said to have been born in ancient times more than 2 billion years ago, are now attracting attention as an energy source for industry. There are two reasons for attention. The first is that we can get a lot of oil, which is an energy source for industry. Currently, the most oily land plant per ^square meter is palm palm produced in Southeast Asia. On the other hand, microalgae are said to produce about 10 times more oil per unit area than palm palm, although it is a theoretical value. The second point is carbon neutral. Microalgae, which are plants, take in carbon dioxide by photosynthesis and proliferate. In addition, waste disposal of energy resources is always a difficult task, but the oil squeezed residue from microalgae is expected to be used for livestock feed and soil improvement, which is a great advantage.

However, at this point, microalgae are still developing as industrial energy. In order to extract oil from microalgae, a work called solid-liquid separation is required to remove cells from water. Nowadays, electric energy and a large amount of capital investment are required, so stable mass production as a profitable biofuel has not yet been realized. Proliferation is not easy either. Research has progressed in the fields of fermentation and brewing using microorganisms, and cultivation techniques and breeding have made considerable progress, but microalgae are still a long way off. Some companies have been spending decades improving microbial breeds to produce more amino acids. However, research on the practical application of microalgae has a short history, and breeding is also in the exploration stage. There are many unclear points about what kind of culture is possible. If all of these are paradoxically taken, the number of challenges is simply the "huge potential." Nowadays, the biofuels produced by microalgae are attracting more attention than ever, and the heat of research is increasing all over the world.

One of the keys to solving the problem is the establishment of a culture method. The number of microalgae increases steadily if the environment is good, but the range of appropriate environment is narrow. For example, Euglena often increases in the temperature range of 25 ° C to 30 ° C. However, it starts to stop growing at 20 ° C and hardly grows at 18 ° C or lower. When growing in a natural environment, Japan cannot secure climatic conditions for stable growth throughout the year. There is also a problem with brightness. Euglena will not grow if the light intensity is too strong. I like the light intensity of rain or cloudy weather.

How can microalgae grow even in the strong light of fine weather? The keyword is in pigments called carotenoids. Carotenoids are pigments produced by the chloroplasts of plants. Carrots have beta-carotene and tomatoes have lycopene. Carotenoids are effective in removing active oxygen in both animals and plants. Especially in places where light gathers, active oxygen is likely to be generated, and if it is not removed, various cells in the body will deteriorate. Conversely, the required amount of carotenoids is effective in maintaining physical health and preventing aging. In fact, when I knocked down a gene with Euglena to make Euglena that could not produce carotenoids, I discovered that a lot of active oxygen was generated and the growth became worse. Conversely, if Euglena with a lot of carotenoids can be produced, it may grow up even with a certain amount of strong light. In this way, if we can understand the characteristics of microalgae, improve the varieties, and expand the range of the appropriate environment for growth, we can contribute to the diversification of the culture environment.

The energy raw materials that support the current social infrastructure are relatively inexpensive. For example, gasoline is regular and rarely exceeds 150 yen per liter. It is cheaper than drinking water from domestic PET bottles, even though it takes time to go to the Middle East, draw crude oil in a tanker, carry it, refine it, and deliver it nationwide. Biofuels have received a lot of attention since the 1970s oil crisis, but eventually disappeared before the existence of cheap energy sources. However, in the 2010s, as global environmental problems became more serious, full-scale research began to proceed again as an important research theme.

The existence of the university comes to life here. I think that human beings should consider the existence of microalgae capable of sustainable production in order to solve the energy problems of society in each era and each region. Nonetheless, private companies are cautious about medium- to long-term investment because their management is evaluated based on their single-year performance, and they make more strict decisions regarding short-term investment payback. On the other hand, universities are easy to live from a medium- to long-term perspective. There are many cases in which basic research on biology and basic research on materials undertaken at universities has proved to be effective for industry after many years, and will change society thereafter. I studied microalgae when I was a Graduate School student, and after that I got a job at a research institute of Hitachi, Ltd. and engaged in research for various industries. After being called by a research team to remove microorganisms from the ballast water of a large tanker, I was once again involved in research on microalgae for industry, and after I retired from the company, I took over the research at Teikyo University. Strangely, I gained the experience of working on microalgae from various standpoints such as corporate position, university position, and social perspective. That is why I strongly feel the possibility of transforming society in the medium- to long-term research conducted by universities.

From the SDGs perspective, the areas covered by microalgae cover a wide range of areas, including energy, food and nutrition issues, and industry in general. In particular, our laboratory has a large number of students who are interested in the theme of the environment. These students also contribute to unique discoveries. There is a pond near the Utsunomiya Campus where only spring water and rainwater can enter, but I discovered that the Pediastrum collected here has the property of storing a large amount of oil only at a certain time. The Pediastrum is isolated and cultured in our laboratory, and the lipid composition and growth characteristics are analyzed. This is exactly the original research that we are working on with the students.

Pediastrum lives in a colony of multiple cells. Especially unique is the way it grows. Normally, in many unicellular organisms, one cell divides into two cells and increases, but in Pediastrum, the cells do not divide in the first place, but repeat nuclear division within one cell. Then, when the same number of nuclei as the cells that make up the colony are formed, the cells divide at once. The cells swim apart for a moment, but soon the cells adhere to each other to form a new colony. A 16-cell colony can grow 16-fold at a time, and a 32-cell colony can grow 32-fold. From the viewpoint of proliferation rate, it can be said to be "explosive". Certainly, at this point, Euglena is in the best position in terms of its effectiveness as a fuel and its usefulness as a cell component that can be used in the food field. However, it is still uncertain whether Euglena will be the final choice for microalgae as a future biofuel. Among the dozens of microalgaes with high lipid production efficiency discovered at this stage, it is possible that a completely new species with another power can be found. By finding a suitable environment for the characteristics and growth of Pediastrum collected by students, there is a good possibility that it will be the most suitable microalgae for biofuels. The solution of SDGs is a global and human issue, and it is very difficult. You need to constantly explore new possibilities, and it's important to strengthen existing possibilities. Even a small plant called microalgae may have the power to brighten the future of humankind. That is why we continue to challenge ourselves to find the key to solving the SDGs issues hidden in our ancient existence and to open the door to the realization of a new sustainable society.