Shinichi Akizuki

Environmental microbial engineering, water treatment engineering, waste treatment engineering, plankton engineering

We aim to develop technologies that create a sustainable environment by utilizing microorganisms, which have acquired diverse metabolic functions during the course of evolution, to enhance and diversify the material cycle within living areas, addressing waste and wastewater, which are inevitably generated as a result of human activities and continue to be a source of pollution for the global environment. We have positioned this academic field based on this concept as "Environmental Creation Microbial Engineering," and we conduct research covering everything from its fundamentals to its applications.
Specifically, our research focuses on the following themes:
1. Energy-saving and resource-recovering wastewater treatment utilizing photosynthetic microorganisms
2. Multifunctionalization of a single reactor through the coexistence of microbial communities
3. Advanced methane fermentation and recovery of inorganic and organic resources
4. AI-powered control of microbial processes
5. Applications of microbial engineering technologies in space environments

1. Development of energy-saving wastewater treatment technology utilizing the functions of photosynthetic microorganisms
   Human activities and wastewater generation are inextricably linked, and proper wastewater treatment is essential to prevent water pollution and the spread of disease. However, existing wastewater treatment technologies have become widespread mainly in developed countries with stable economic foundations and the ability to invest in environmental protection measures, making it difficult to directly implement them in developing countries where economic growth is the primary concern rather than environmental protection.
   My research focuses on wastewater treatment using photosynthetic microorganisms that utilize the nearly limitless energy of sunlight. For example, instead of the conventional activated sludge method which requires mechanical aeration, I am conducting research on wastewater treatment using a "microalgae-bacteria symbiosis system" that combines photosynthesis by microalgae with the removal of organic pollutants by bacteria. I am also researching wastewater treatment using "purple photosynthetic bacteria," which have the characteristic of accumulating useful components such as proteins, carbohydrates, PHA, and carotenoids in their bodies by utilizing organic pollutants and nutrients in wastewater. These technologies are particularly suitable for use in relatively warm, sun-rich regions located between 35 degrees north and 35 degrees south latitude, known as the Sun Belt. The Sun Belt region is home to many developing countries in Central and South America, Africa, and Southeast Asia, where wastewater treatment is not widely available. By advancing the research and development of this technology and accumulating knowledge and know-how, I expect it to mature into a next-generation wastewater treatment technology that can be introduced and disseminated regardless of economic infrastructure. Our university primarily conducts basic research, while applied research and practical testing are carried out in collaboration with partner research institutions in Mexico, Ethiopia, and other countries.
   Relevant project:
   Development of nitrogen-containing wastewater treatment technology using a microalgae-nitrification symbiotic process with a fluid carrier.
   Japan Society for the Promotion of Science (JSPS) Grants-in-Aid for Scientific Research, Young Scientists (B) 17K12851 (2017-2018), Principal Investigator
   URL: https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-17K12851/
   Treatment of high-concentration nitrogen-containing wastewater using a microalgae-nitrification-denitrification symbiotic system with sponge carriers
   Japan Society for the Promotion of Science Overseas Research Fellow 201860754 (2018-2020) Principal Investigator
   URL: https://www.jsps.go.jp/j-ab/ab_list/list_h30.html
   Low-cost treatment of nitrogen-containing wastewater using microalgae-nitrifying bacteria immobilized in light-shielding gel: A case study from Mexico.
   Japan Society for the Promotion of Science (JSPS) Grants-in-Aid for Scientific Research, International Collaborative Research Acceleration Fund (Enhancing International Collaborative Research (B)) 20KK0249 (2020-2024) Research Collaborator
   URL: https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-20KK0249/
   Purple photosynthetic bacteria—methane fermentation symbiotic system for advanced treatment of poultry farm wastewater and production of useful substances
   Maekawa Ho-onkai 2020 Academic Research Grant (2020-2022) Principal Investigator
    
2. Development of resource-recycling urine treatment technology for long-term manned operations on the lunar surface
   Space is the greatest frontier left for humankind. Its exploration will expand humanity's living and activity spheres, lead to the acquisition of useful mineral resources, advancements in science and technology through research utilizing the space environment, and the creation of space-utilization industries, thereby greatly contributing to the development of a prosperous and sustainable society. In recent years, the space exploration race among developed countries has intensified, with space development agencies such as NASA and JAXA, as well as those in Europe, China, and India, advancing their projects. There is a common understanding that the next 30 years will focus particularly on lunar exploration, aiming to construct a manned settlement on the lunar surface by the 2040s and begin industrial use such as intervention by private companies and tourism by the general public. In a settlement to be established on the lunar surface, resources essential for human survival, such as water, oxygen, and food, are extremely limited. Therefore, technology for recycling resources within the settlement is indispensable for long-term manned activities. Urine, in particular, is produced daily and contains abundant nutrients such as nitrogen and phosphorus, so it is considered one of the resources that should be utilized most during long-term manned activities in space.
   Microalgae can purify nutrients in urine through photosynthesis, and the resulting microalgae biomass has the potential to be used in functional foods, biofuels, animal feed, and other applications. Furthermore, since they can remove carbon dioxide and supply oxygen, which are essential for sustaining life in space facilities, urine treatment using microalgae is considered a suitable technology for lunar habitats. In my research, I am conducting basic research, such as investigating how microgravity environments affect the metabolism of microalgae, with the aim of establishing a circular utilization technology for urine resources starting with microalgae.
   Relevant project:
   Lunar regolith immersion – Development of lunar urine treatment technology using a system of coexistence between microalgae and agglutinating nitrifying bacteria
   Japan Society for the Promotion of Science (JSPS) Grants-in-Aid for Scientific Research (B) 21H03665 (2021-2024) Principal Investigator
   URL: https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-21H03665/
    
3. Development of a high-speed methane fermentation technology for the excessive growth of aquatic plant biomass in Lake Tana, Ethiopia
   Lake Tana, the source of the Nile River, is a vast lake known for its rich natural environment and scenic beauty. However, currently, more than 500 km2 of the lake's surface, equivalent to the area of Tokyo's 23 wards, is covered with water hyacinths, causing damage to more than 500,000 people engaged in agriculture and fisheries. Establishing appropriate management and treatment methods has become a national priority. Since 2020, our university has been working to solve these problems with the support of the Science and Technology Research Partnership for Sustainable Development (SATREPS) program, sponsored by the Japan Science and Technology Agency (JST) and the Japan International Cooperation Agency (JICA). Specifically, we aim to develop a system for managing water hyacinths in Lake Tana using Information and Communication Technology (ICT), such as remote sensing technology, and for converting the collected water hyacinths into valuable materials (microalgae, agricultural products, etc.) through high-speed methane fermentation and carbonization after compression. In my research, I am working towards developing a high-speed methane fermentation technology for water hyacinth extract. This involves investigating energy-saving and low-cost pretreatment methods for the extract, as well as a fixed-bed methane fermentation method that utilizes locally available waste materials such as bagasse as microbial carriers.
   Relevant project:
   Establishment of management methods and effective utilization processes for excessive aquatic plant biomass in Lake Tana, Ethiopia, the source of the Nile.
   Japan Science and Technology Agency (JST) Japan International Cooperation Agency (JICA) Science and Technology Cooperation Program for Sustainable Development (2020-2025) Research Collaborator (Theme 2 Leader), Project Manager
   URL: https://www.jst.go.jp/global/kadai/r0205_ethiopia.html
   https://www.youtube.com/watch?v=WdPNfQOv3Lk

[Undergraduate] Plankton Engineering, Water Treatment Engineering Experiment, Environmental Analytical Chemistry Experiment
[Graduate School] Restoration Ecology

[Education]
2010 Graduated from Soka University, Faculty of Engineering, Department of Environmental Symbiotic Engineering, Bachelor of Engineering
2012 Completed Master's Program in Engineering at Soka University Graduate School of Engineering Environmental Engineering for Symbiosis Major Master's Program
2015 Completed Doctoral Program at Soka University Graduate School of Engineering, Environmental Engineering for Symbiosis Major Doctoral Program Doctoral Program, Ph.D. in Engineering
[Work History]
2015: Assistant Professor, Faculty of Science and Technology, Soka University
2018 Japan Society for the Promotion of Science Overseas Research Fellow (Dispatched to: Mexico University of Guanajuato Faculty of Engineering)
2020 Soka University Institute of Plankton Eco-engineering Lecturer
2024 Soka University Institute of Plankton Eco-engineering Specially Appointed Associate Professor
2026: Associate Professor, Faculty of Science and Engineering, Soka University
2015: Assistant Professor, Faculty of Science and Technology, Soka University
2018 Japan Society for the Promotion of Science Overseas Research Fellow (Dispatched to: Mexico University of Guanajuato Faculty of Engineering)
2020 Soka University Institute of Plankton Eco-engineering Lecturer

Japanese Society of Water Environment, Japanese Society of Microbial Ecology, International Water Association

[Peer-reviewed academic papers (excerpts)]

1. Akizuki, S., Cuevas-Rodríguez, G. (2025). Microalgae assisted coupled nitrification-denitrification in a sponge-based trickling photobioreactor during anaerobic digestate treatment. Chemical Engineering Journal, 520, 165712. https://doi.org/10.1016/j.cej.2025.165712
2.  Akizuki, S., Ida, J. (2025). Impact of simulated microgravity on the activity of nitrifying sludge under dissolved oxygen-limited conditions. Microgravity Science and Technology, 37, 41.  https://doi.org/10.1007/s12217-025-10189-1
3. Bhatia, P., Fujiwara, M., Akizuki, S., Maruyama, D., Habtu, N. G., Sato, S., Toda, T. (2025). High-rate anaerobic digestion of water hyacinth juice in an upflow anaerobic sludge blanket reactor with observations on granule formation. Journal of Water Process Engineering, 72,  107339. https://doi.org/10.1016/j.jwpe.2025.107339
4. Nishi, K., Akizuki, S., Toda, T., Matsuyama, T., Ida, J. (2023). Effects of different biomass ratios of light-tolerant microalgae-nitrifying bacteria consortia on ammonia removal. Biochemical Engineering Journal, 193, 108872. https://doi.org/10.1016/j.bej.2023.108872
5. Akizuki, S., Suzuki, H., Fujiwara, M., Toda, T. (2023). Impacts of steam explosion pretreatment on semi-continuous anaerobic digestion of lignin-rich submerged macrophyte. Journal of Cleaner Production, 380, 135377. https://doi.org/10.1016/j.jclepro.2022.135377
6. Salangsang, M.C.D., Sekine, M., Akizuki, S., Sakai, H.D., Kurosawa, N., Toda, T. (2022). Effect of carbon to nitrogen ratio of food waste and short resting period on microbial accumulation during anaerobic digestion. Biomass and Bioenergy, 166, 106481. https://doi.org/10.1016/j.biombioe.2022.106481
7. Nishi, K., Akizuki, S., Toda, T., Matsuyama, T., Ida, J. (2022). Advanced light-tolerant microalgae-nitrifying bacteria consortia for stable ammonia removal under strong light irradiation using light-shielding hydrogel. Chemosphere, 297, 134252. https://doi.org/10.1016/j.chemosphere.2022.134252
8. Mata-De-la-Vega, J.F., Akizuki, S., Sakai, H.D., Cuevas-Rodríguez, G. (2022). Slaughterhouse wastewater treatment using purple phototrophic bacteria: A comparison between photoheterotrophic and chemoheterotrophic conditions. Biochemical Engineering Journal, 179, 108273. https://doi.org/10.1016/j.bej.2021.108273
9. Akizuki, S., Cuevas-Rodríguez, G., Toda, T. (2021). Nitrification of anaerobic digestate using a consortium of microalgae and nitrifiers in an open photobioreactor with moving bed carriers. Chemosphere, 263, 127948. https://doi.org/10.1016/j.chemosphere.2020.127948
10. Akizuki, S., Kishi, M., Cuevas-Rodríguez, G., Toda, T. (2020). Effects of different light conditions on ammonium removal in a consortium of microalgae and partial nitrifying granules. Water Research, 171, 115445. https://doi.org/10.1016/j.watres.2019.115445
11. Nishi, K., Akizuki, S., Toda, T., Matsuyama, T., Ida, J. (2020). Development of light-shielding hydrogel for nitrifying bacteria to prevent photoinhibition under strong light irradiation. Process Biochemistry, 94, 359–364. https://doi.org/10.1016/j.procbio.2020.04.037
12. Akizuki, S., Cuevas-Rodríguez, G., Toda, T. (2019). Microalgal-nitrifying bacterial consortium for energy-saving ammonia removal from anaerobic digestate of slaughterhouse wastewater. Journal of Water Process Engineering, 31, 100753. https://doi.org/10.1016/j.jwpe.2019.01.014

[Book (excerpt)]

1. Akizuki, Shinichi. Chapter 5, "From Earth to Space," in Toda, Ryuki, Ida, Junichi, and Sato, Shinjiro (eds.), *Green Technology to Save the Earth*, Daisan Bunmei-sha, 2025. ISBN 978-4-476-03434-9.
2. Akizuki, S., Sato, S., Legesse, S.A., Cuevas-Rodríguez, G. (2021). Treatment of piggery wastewater with an integrated microalgae-nitrifiers process: current status and prospects. In: Integrated and Hybrid Process Technology for Water and   Wastewater Treatment, 595–616. https://doi.org/10.1016/B978-0-12-823031-2.00021-5

Environmental microbial engineering, water treatment engineering, waste treatment engineering, plankton engineering

We aim to develop technologies that create a sustainable environment by utilizing microorganisms, which have acquired diverse metabolic functions during the course of evolution, to enhance and diversify the material cycle within living areas, addressing waste and wastewater, which are inevitably generated as a result of human activities and continue to be a source of pollution for the global environment. We have positioned this academic field based on this concept as "Environmental Creation Microbial Engineering," and we conduct research covering everything from its fundamentals to its applications.
Specifically, our research focuses on the following themes:
1. Energy-saving and resource-recovering wastewater treatment utilizing photosynthetic microorganisms
2. Multifunctionalization of a single reactor through the coexistence of microbial communities
3. Advanced methane fermentation and recovery of inorganic and organic resources
4. AI-powered control of microbial processes
5. Applications of microbial engineering technologies in space environments

1. Development of energy-saving wastewater treatment technology utilizing the functions of photosynthetic microorganisms
   Human activities and wastewater generation are inextricably linked, and proper wastewater treatment is essential to prevent water pollution and the spread of disease. However, existing wastewater treatment technologies have become widespread mainly in developed countries with stable economic foundations and the ability to invest in environmental protection measures, making it difficult to directly implement them in developing countries where economic growth is the primary concern rather than environmental protection.
   My research focuses on wastewater treatment using photosynthetic microorganisms that utilize the nearly limitless energy of sunlight. For example, instead of the conventional activated sludge method which requires mechanical aeration, I am conducting research on wastewater treatment using a "microalgae-bacteria symbiosis system" that combines photosynthesis by microalgae with the removal of organic pollutants by bacteria. I am also researching wastewater treatment using "purple photosynthetic bacteria," which have the characteristic of accumulating useful components such as proteins, carbohydrates, PHA, and carotenoids in their bodies by utilizing organic pollutants and nutrients in wastewater. These technologies are particularly suitable for use in relatively warm, sun-rich regions located between 35 degrees north and 35 degrees south latitude, known as the Sun Belt. The Sun Belt region is home to many developing countries in Central and South America, Africa, and Southeast Asia, where wastewater treatment is not widely available. By advancing the research and development of this technology and accumulating knowledge and know-how, I expect it to mature into a next-generation wastewater treatment technology that can be introduced and disseminated regardless of economic infrastructure. Our university primarily conducts basic research, while applied research and practical testing are carried out in collaboration with partner research institutions in Mexico, Ethiopia, and other countries.
   Relevant project:
   Development of nitrogen-containing wastewater treatment technology using a microalgae-nitrification symbiotic process with a fluid carrier.
   Japan Society for the Promotion of Science (JSPS) Grants-in-Aid for Scientific Research, Young Scientists (B) 17K12851 (2017-2018), Principal Investigator
   URL: https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-17K12851/
   Treatment of high-concentration nitrogen-containing wastewater using a microalgae-nitrification-denitrification symbiotic system with sponge carriers
   Japan Society for the Promotion of Science Overseas Research Fellow 201860754 (2018-2020) Principal Investigator
   URL: https://www.jsps.go.jp/j-ab/ab_list/list_h30.html
   Low-cost treatment of nitrogen-containing wastewater using microalgae-nitrifying bacteria immobilized in light-shielding gel: A case study from Mexico.
   Japan Society for the Promotion of Science (JSPS) Grants-in-Aid for Scientific Research, International Collaborative Research Acceleration Fund (Enhancing International Collaborative Research (B)) 20KK0249 (2020-2024) Research Collaborator
   URL: https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-20KK0249/
   Purple photosynthetic bacteria—methane fermentation symbiotic system for advanced treatment of poultry farm wastewater and production of useful substances
   Maekawa Ho-onkai 2020 Academic Research Grant (2020-2022) Principal Investigator
    
2. Development of resource-recycling urine treatment technology for long-term manned operations on the lunar surface
   Space is the greatest frontier left for humankind. Its exploration will expand humanity's living and activity spheres, lead to the acquisition of useful mineral resources, advancements in science and technology through research utilizing the space environment, and the creation of space-utilization industries, thereby greatly contributing to the development of a prosperous and sustainable society. In recent years, the space exploration race among developed countries has intensified, with space development agencies such as NASA and JAXA, as well as those in Europe, China, and India, advancing their projects. There is a common understanding that the next 30 years will focus particularly on lunar exploration, aiming to construct a manned settlement on the lunar surface by the 2040s and begin industrial use such as intervention by private companies and tourism by the general public. In a settlement to be established on the lunar surface, resources essential for human survival, such as water, oxygen, and food, are extremely limited. Therefore, technology for recycling resources within the settlement is indispensable for long-term manned activities. Urine, in particular, is produced daily and contains abundant nutrients such as nitrogen and phosphorus, so it is considered one of the resources that should be utilized most during long-term manned activities in space.
   Microalgae can purify nutrients in urine through photosynthesis, and the resulting microalgae biomass has the potential to be used in functional foods, biofuels, animal feed, and other applications. Furthermore, since they can remove carbon dioxide and supply oxygen, which are essential for sustaining life in space facilities, urine treatment using microalgae is considered a suitable technology for lunar habitats. In my research, I am conducting basic research, such as investigating how microgravity environments affect the metabolism of microalgae, with the aim of establishing a circular utilization technology for urine resources starting with microalgae.
   Relevant project:
   Lunar regolith immersion – Development of lunar urine treatment technology using a system of coexistence between microalgae and agglutinating nitrifying bacteria
   Japan Society for the Promotion of Science (JSPS) Grants-in-Aid for Scientific Research (B) 21H03665 (2021-2024) Principal Investigator
   URL: https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-21H03665/
    
3. Development of a high-speed methane fermentation technology for the excessive growth of aquatic plant biomass in Lake Tana, Ethiopia
   Lake Tana, the source of the Nile River, is a vast lake known for its rich natural environment and scenic beauty. However, currently, more than 500 km2 of the lake's surface, equivalent to the area of Tokyo's 23 wards, is covered with water hyacinths, causing damage to more than 500,000 people engaged in agriculture and fisheries. Establishing appropriate management and treatment methods has become a national priority. Since 2020, our university has been working to solve these problems with the support of the Science and Technology Research Partnership for Sustainable Development (SATREPS) program, sponsored by the Japan Science and Technology Agency (JST) and the Japan International Cooperation Agency (JICA). Specifically, we aim to develop a system for managing water hyacinths in Lake Tana using Information and Communication Technology (ICT), such as remote sensing technology, and for converting the collected water hyacinths into valuable materials (microalgae, agricultural products, etc.) through high-speed methane fermentation and carbonization after compression. In my research, I am working towards developing a high-speed methane fermentation technology for water hyacinth extract. This involves investigating energy-saving and low-cost pretreatment methods for the extract, as well as a fixed-bed methane fermentation method that utilizes locally available waste materials such as bagasse as microbial carriers.
   Relevant project:
   Establishment of management methods and effective utilization processes for excessive aquatic plant biomass in Lake Tana, Ethiopia, the source of the Nile.
   Japan Science and Technology Agency (JST) Japan International Cooperation Agency (JICA) Science and Technology Cooperation Program for Sustainable Development (2020-2025) Research Collaborator (Theme 2 Leader), Project Manager
   URL: https://www.jst.go.jp/global/kadai/r0205_ethiopia.html
   https://www.youtube.com/watch?v=WdPNfQOv3Lk

[Undergraduate] Plankton Engineering, Water Treatment Engineering Experiment, Environmental Analytical Chemistry Experiment
[Graduate School] Restoration Ecology

[Education]
2010 Graduated from Soka University, Faculty of Engineering, Department of Environmental Symbiotic Engineering, Bachelor of Engineering
2012 Completed Master's Program in Engineering at Soka University Graduate School of Engineering Environmental Engineering for Symbiosis Major Master's Program
2015 Completed Doctoral Program at Soka University Graduate School of Engineering, Environmental Engineering for Symbiosis Major Doctoral Program Doctoral Program, Ph.D. in Engineering
[Work History]
2015: Assistant Professor, Faculty of Science and Technology, Soka University
2018 Japan Society for the Promotion of Science Overseas Research Fellow (Dispatched to: Mexico University of Guanajuato Faculty of Engineering)
2020 Soka University Institute of Plankton Eco-engineering Lecturer
2024 Soka University Institute of Plankton Eco-engineering Specially Appointed Associate Professor
2026: Associate Professor, Faculty of Science and Engineering, Soka University
2015: Assistant Professor, Faculty of Science and Technology, Soka University
2018 Japan Society for the Promotion of Science Overseas Research Fellow (Dispatched to: Mexico University of Guanajuato Faculty of Engineering)
2020 Soka University Institute of Plankton Eco-engineering Lecturer

Japanese Society of Water Environment, Japanese Society of Microbial Ecology, International Water Association

[Peer-reviewed academic papers (excerpts)]

1. Akizuki, S., Cuevas-Rodríguez, G. (2025). Microalgae assisted coupled nitrification-denitrification in a sponge-based trickling photobioreactor during anaerobic digestate treatment. Chemical Engineering Journal, 520, 165712. https://doi.org/10.1016/j.cej.2025.165712
2.  Akizuki, S., Ida, J. (2025). Impact of simulated microgravity on the activity of nitrifying sludge under dissolved oxygen-limited conditions. Microgravity Science and Technology, 37, 41.  https://doi.org/10.1007/s12217-025-10189-1
3. Bhatia, P., Fujiwara, M., Akizuki, S., Maruyama, D., Habtu, N. G., Sato, S., Toda, T. (2025). High-rate anaerobic digestion of water hyacinth juice in an upflow anaerobic sludge blanket reactor with observations on granule formation. Journal of Water Process Engineering, 72,  107339. https://doi.org/10.1016/j.jwpe.2025.107339
4. Nishi, K., Akizuki, S., Toda, T., Matsuyama, T., Ida, J. (2023). Effects of different biomass ratios of light-tolerant microalgae-nitrifying bacteria consortia on ammonia removal. Biochemical Engineering Journal, 193, 108872. https://doi.org/10.1016/j.bej.2023.108872
5. Akizuki, S., Suzuki, H., Fujiwara, M., Toda, T. (2023). Impacts of steam explosion pretreatment on semi-continuous anaerobic digestion of lignin-rich submerged macrophyte. Journal of Cleaner Production, 380, 135377. https://doi.org/10.1016/j.jclepro.2022.135377
6. Salangsang, M.C.D., Sekine, M., Akizuki, S., Sakai, H.D., Kurosawa, N., Toda, T. (2022). Effect of carbon to nitrogen ratio of food waste and short resting period on microbial accumulation during anaerobic digestion. Biomass and Bioenergy, 166, 106481. https://doi.org/10.1016/j.biombioe.2022.106481
7. Nishi, K., Akizuki, S., Toda, T., Matsuyama, T., Ida, J. (2022). Advanced light-tolerant microalgae-nitrifying bacteria consortia for stable ammonia removal under strong light irradiation using light-shielding hydrogel. Chemosphere, 297, 134252. https://doi.org/10.1016/j.chemosphere.2022.134252
8. Mata-De-la-Vega, J.F., Akizuki, S., Sakai, H.D., Cuevas-Rodríguez, G. (2022). Slaughterhouse wastewater treatment using purple phototrophic bacteria: A comparison between photoheterotrophic and chemoheterotrophic conditions. Biochemical Engineering Journal, 179, 108273. https://doi.org/10.1016/j.bej.2021.108273
9. Akizuki, S., Cuevas-Rodríguez, G., Toda, T. (2021). Nitrification of anaerobic digestate using a consortium of microalgae and nitrifiers in an open photobioreactor with moving bed carriers. Chemosphere, 263, 127948. https://doi.org/10.1016/j.chemosphere.2020.127948
10. Akizuki, S., Kishi, M., Cuevas-Rodríguez, G., Toda, T. (2020). Effects of different light conditions on ammonium removal in a consortium of microalgae and partial nitrifying granules. Water Research, 171, 115445. https://doi.org/10.1016/j.watres.2019.115445
11. Nishi, K., Akizuki, S., Toda, T., Matsuyama, T., Ida, J. (2020). Development of light-shielding hydrogel for nitrifying bacteria to prevent photoinhibition under strong light irradiation. Process Biochemistry, 94, 359–364. https://doi.org/10.1016/j.procbio.2020.04.037
12. Akizuki, S., Cuevas-Rodríguez, G., Toda, T. (2019). Microalgal-nitrifying bacterial consortium for energy-saving ammonia removal from anaerobic digestate of slaughterhouse wastewater. Journal of Water Process Engineering, 31, 100753. https://doi.org/10.1016/j.jwpe.2019.01.014

[Book (excerpt)]

1. Akizuki, Shinichi. Chapter 5, "From Earth to Space," in Toda, Ryuki, Ida, Junichi, and Sato, Shinjiro (eds.), *Green Technology to Save the Earth*, Daisan Bunmei-sha, 2025. ISBN 978-4-476-03434-9.
2. Akizuki, S., Sato, S., Legesse, S.A., Cuevas-Rodríguez, G. (2021). Treatment of piggery wastewater with an integrated microalgae-nitrifiers process: current status and prospects. In: Integrated and Hybrid Process Technology for Water and   Wastewater Treatment, 595–616. https://doi.org/10.1016/B978-0-12-823031-2.00021-5