Hokkaido University Research Profiles


Environment: 12

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  • Life Sciences
  • Information and Communication
  • Nanotechnology / Materials
  • Manufacturing Technology
  • Human and Social Sciences
  • Energy
  • Environment
  • Tourism / Community development
  • Arctic Research
  • Social Infrastructure
  • Open Facilities
  • Ecosystem Restoration of Disturbed Areas

    Promoting eco-friendly restoration of ecosystems that have been disturbed by natural or human activities through facilitation.

    Facilitation refers to a phenomenon whereby the establishment of a certain plant prompts the invasion and establishment of another species. In ecosystems that have suffered catastrophic damage due to a major disturbance such as a volcanic eruption, fire, tsunami or mining, the detection and introduction of such facilitators will help rapid and eco-friendly ecosystem restoration.

    • Fig. Platanthera metabifolia, which has taken root in a patch of Mineyanagi willow on Mt. Komagatake in Oshima after its major eruption in 1920.
      The Mineyanagi willow promotes the colonization by many species and thereby enhances ecological diversity .

    • Fig. Relationship between coverage of M. sinensis, a facilitator, and the number/density of woody plants on a ski slope in Sapporo (plot size: 4 m2).
      The colonization of M. sinensis prompts an increase in the number of woody plants, so the creation of M. sinensis grasslands will lead to the growth of natural forests without afforestation efforts.


    Ecosystem restoration after large-scale disturbance is often an urgent task, but it has often been difficult to establish a target plant species in a disturbed environment. A facilitator is a plant species that prompts the establishment of other species once it has been established. If we can detect and establish a facilitator in the respective disturbed areas to prompt the invasion and establishment of the target species there, it will be possible to quickly restore ecosystems in a cost-effective manner with minimal human effort. Therefore, this is an ecofriendly technology for ecosystem restoration.
    So far, we have found that the white beak-sedge (Rhynchospora) is functioning as a facilitator in the post-mined peatland of Sarobetsu Mire, and the Mineyanagi willow in Mt. Komagatake in Oshima, Hokkaido. Microtopography modification has also been found effective as a means of introducing facilitators.

  • A New Plant Growth Promotion Technology That Stimulates Growth

    Next generation biomass production using wastewater and the possibility of using symbiotic bacteria for plant factories

    A completely new growth-promoting bacterium, P23, was discovered in ukikusa (subfamily Lemnoideae) at the Hokkaido University Botanical Garden. The P23 bacterium accelerates the growth of plants by stimulating a surface switch. Ukikusa is a high value-added biomass that grows on wastewater as a fertilizer, and symbiosis with P23 doubles its production rate.


    The aquatic plant known as ukikusa is a soft biomass that can grow by absorbing nitrogen and phosphorus from wastewater and contains almost no lignin or cellulose. Its protein content is approximately 30%, comparable to that of soybeans, and its starch accumulation can reach 50%, depending on the growth environment. Its protein can be used directly as livestock feed, while its starch is useful as a raw material for biofuel production and the production of HMF, a precursor for chemical products. To improve the production yield of the next generation biomass, we are developing technology to promote plant growth with the symbiotic action of surface bacteria. In addition to ukikusa cultivation, it is expected to apply this technology to hydroponic cultivation of vegetables and cereals (plant factories). This is an old but new biotechnology that does not involve genetic modification and follows the natural order of things.

    Masaaki Morikawa Professor
    Doctor of Engineering
  • Capturing and Insolubilization of Cesium by Aluminosilicates

    Capturing of cesium contained in decontamination waste by aluminosilicate (alkali feldspar)

    The insoluble form of cesium in incineration bottom ash was concentrated in the amorphous phase on the surface of a specific mineral, namely, alkali feldspar. This trapping phenomenon is applied to insolubilize cesium in soil and waste generated during decontamination, and we are developing a technology to control the leaching of cesium, even during long-term storage.


    The solubility of cesium (Cs) in incineration bottom ash is low due to strong trapping of Cs in the amorphous phase on the surface of microcline, which is a kind of alkali feldspar. When Cs salts such as Cs carbonate and Cs chloride are added to pure microcline and heated, Cs is trapped at an extremely high rate and becomes insoluble (Fig. 1). Since the Cs trapped by this process is fixed very tightly, it cannot be extracted unless hydrofluoric acid is used. Similar Cs trapping occurs when using a reagent to synthesize microcline (Fig. 2). In this study, we are applying this phenomenon of Cs capture by microcline (aluminosilicate) to Cs-enriched materials (e.g., fly ash with high Cs concentration) generated during volume reduction thermal treatment of removed soil and decontamination waste, aiming to establish a technology to reduce the mobility of Cs in the waste to be finally disposed of to the extent possible (Fig. 3).

  • Catalytic Purification of Nitrate-nitrogen Contaminated Water

    High-performance catalyst for reductive decomposition of nitrate-nitrogen

    Groundwater pollution with nitrate-nitrogen has become a problem. We have developed a high-performance solid catalyst that promotes decomposition of nitrate-nitrogen in water into nitrogen gas through a reaction with hydrogen gas at room temperature. Using a purification system incorporating this catalyst, we have succeeded in purifying contaminated groundwater.


    Groundwater pollution with nitrate-nitrogen has become a nationwide problem. We have developed a high-performance solid catalyst that promotes decomposition of nitrate-nitrogen in groundwater into nitrogen gas, and have also succeeded in purifying actual contaminated groundwater using a purification system incorporating the developed catalyst.
    The treatment of water containing nitrate-nitrogen is predominantly a biological treatment that involves anaerobic and aerobic treatment. The equipment for that is generally large and its operation is complicated. The catalytic water purification system we have developed is very compact and does not require complicated operations, making it possible to purify contaminated water simply by passing hydrogen gas and contaminated water through a temperature-controlled reactor filled with catalyst.

  • Control of Sedimentation and Diffusion Behavior Using the Collectivity of Particles in Liquid

    Free control of the settling behavior of particles

    We introduce technologies to accelerate the sedimentation rate and control the dispersion behavior of particles in complex channels by taking advantage of the collective nature of particles observed when there is a difference in the concentration of the suspension.


    We propose technologies to actively control the sedimentation rate and dispersion behavior by effectively using the collective nature of particles in liquid caused by concentration differences. When suspension conditions change, heterogeneously dispersed particles show collective sedimentation behavior. We aim to understand the behavior of particles near the concentration interface, which is closely associated with such collective behavior, to actively use it to promote sedimentation, control dispersion and improve transport efficiency, all of which are important in various engineering processes.

  • Detoxification and Removal of Nitrogen from Carbon Resources Using Nanoparticles

    Use of nanoparticles for fuel nitrogen pre-removal and high-temperature gas purification

    To establish principles for advanced utilization of carbon resources in harmony with the global environment is one of the most important research themes for the next generation. With this study, we aim to develop a catalytic process that can efficiently convert carbon resources into clean energy using nanoscale metal and metal oxide particles.


    Nitrogen in carbon resources (Fuel-N) is emitted as NOx and N2O during combustion. During high-temperature gasification, it is mainly converted to NH3, which becomes a source of NOx in later-stage gas combustion. With this study, we have worked on the development of a method to convert Fuel-N into harmless N2 through a pyrolysis process prior to combustion or gasification, and found that Ca ions supported by the ion-exchange method change into CaO nanoparticles during pyrolysis and catalyze the formation of N2 formation.
    We have also found that Fe ions, which are originally contained in lignite coal, and FeOOH, which is abundantly found in brown iron ore, readily become metallic iron nanoparticles during the heating process, and that N2 is selectively produced during the decomposition reaction of NH3, pyridine and pyrrole by this catalyst. Since these N-containing species are contained in the crude gas produced during coal gasification, we are working to develop a new high-temperature gas purification method for the removal of these compounds.

  • Development of Den-type Traps to Reduce the Cost of Non-native Raccoon Control

    To establish an effective and efficient pest control method in low-density situations

    We have been conducting research on measures to control alien species that have been brought into Japan, with the aim of proposing effective control technologies and strategies that can match the ecological and behavioral characteristics of the target species and respond to the conditions of human society. In this study, we developed an efficient trap based on the tree-cave nesting habit of raccoons.


    Control of non-native raccoons, which are increasing in number and causing damage in Hokkaido and other parts of Japan, is an urgent policy issue, and reducing the cost of the prolonged control project is the most important issue in the field. Conventional trapping methods rely only on box traps with bait, and require daily patrols and inspections regardless of whether raccoons have been trapped or not, to prevent bycatch of other animals and to replace bait, and the amount of work does not decrease, even after the population density has been reduced. The den-type trap developed in this study, based on the nesting habit of raccoons in tree caves, does not require bait to attract raccoons, reduces bycatch, and eliminates the need for daily inspections, thereby keeping the cost of pest control extremely low. The trap is also equipped with a system that allows the office to receive capture information via radio waves, making it possible for a small number of people to implement a wide range of pest control measures with a low budget.

    Tohru Ikeda Professor
  • Environmentally Friendly Marine Biofouling Prevention Compounds Derived from Biomass

    Toxic marine anti-biofouling agents against barnacles and other marine organisms are causing pollution to the marine environment, and it is necessary to develop safe alternatives. We have succeeded in creating potent and low-toxicity compounds by synthesizing biomass-derived compounds. Further optimization is also possible.


    The use of the ocean by mankind (e.g., ships and cooling pipes for power plants) is essential, but marine fouling organisms such as barnacles impairs the fuel efficiency of ships and obstructs the functions, for example by clogging. Organotin compounds have been used to prevent functional impairment, but their use has been banned due to their toxicity, and the development of alternatives is desired. We are focusing on compounds used by marine organisms such as nudibranchs to protect against fouling by other organisms. As a result of synthesizing the compounds, we found functional groups (anti-fouling units) that are important for anti-fouling. The functional group was introduced into inexpensive biomass derived from marine organisms in a short process, and when the synthetic product was tested for anti-fouling (cypris larvae of striped barnacles), they were found to have both very strong anti-fouling activity and very weak toxicity. We are currently conducting research on the synthesis of similar compounds and the addition of further functions.

  • Exploration of Marine Phytoplankton from Space

    Development of techniques for classification exploration and quantification of phytoplankton in the ocean using satellites

    We are developing a method to remotely survey floating microalgae (phytoplankton) in the ocean using earth observation satellites. We are currently examining a method to quantitatively observe the world’s largest number of taxonomic groups (11 groups) for remote sensing.


    Phytoplankton in the ocean is a primary producer that supports bioenergy production required for fish production, and the abundance ratios among different kinds of phytoplankton can be used as an indicator of different ecosystem structures (and thus different biological resources). It is expected that the application of satellite exploration technology will enable us to understand where, when, and how different ecosystem structures are fluctuating around the world, which will in turn enable efficient exploration, evaluation and management of biological and fishery resources.

    Takafumi Hirata Specially Appointed Associate Professor
  • Research on Biomass Utilization as a Socio-Technical Systems

    Aiming to spread bioenergy through local circulation

    At the Laboratory of Sustainable Material Cycle Systems research is conducted on the development of technologies and social systems (socio-technical systems) to create locally distributed bioenergy from biomass such as food waste, sewage sludge, livestock manure, forest residues and rice straw.


    We are proposing a system (e.g., planning, modeling and evaluation based on experiments and field studies) that can contribute to both the environment and regional development (economy) by linking energy recovered from biomass (e.g., food waste, sewage sludge, livestock manure, forest residues, and rice straw) through combustion and methane fermentation with local energy consumers (e.g., public facilities, nursing and welfare facilities, agricultural facilities such as greenhouses and food factories). Furthermore, by obtaining cooperation from private companies, we are conducting research on creation of community through biomass utilization in collaboration with the endowed laboratory of biomass community planning (Visiting Professor Toru Furuichi, Specially Appointed Assistant Professor Satoru Ochiai, https://smcs.eng.hokudai.ac.jp/bio-com-p.html).

  • Simple Pathogen Measuring Devices

    Pathogens can be measured by simply adding samples to the kit.

    We have developed technology that allows measurement of the concentration of E. coli, coliforms, and enterococci within as early as 1 hour and as late as 12 hours after simply adding 0.1 mL of a sample (sewage, wastewater, food extract, drinking water) to the measurement kit and installing it in the device.


    Currently, the measurement of pathogenic bacteria requires a much time and labor, including the preparation of agar media, multiple dilutions of a large amount of sample, and 24-hour incubation. We have developed a kit that can measure pathogenic bacteria (fecal contamination indicator bacteria) such as E. coli, coliforms, and enterococci simply by injecting 0.1 mL of liquid sample or food extract. Compared to the current general bacteria measurement technology, this is an extremely simple technology that requires only mixing of the sample with the solution. The bacterial concentration is measured using a fluorescent dye. The fluorescent dye can be used even if the liquid is turbid, so the concentrations of various bacteria, even in turbid samples such as wastewater or food extracts, can be measured directly without any pretreatment.

  • Structural Analysis of Polysaccharides and Proteins That Cause Membrane Fouling

    Although membrane treatment is attracting attention as a next-generation water treatment technology, the degradation of membrane permeability (membrane fouling) has been a barrier to its widespread use. In this study, we conducted the world’s first structural analysis of polysaccharides and proteins, which are the main causes of membrane fouling, for the rational control of membrane fouling.


    Membrane fouling (decrease in membrane permeability) is mainly caused by polysaccharides and proteins produced by microorganisms. However, it is still unclear which polysaccharides and proteins play an important role in that mechanism, and efficient methods to control membrane fouling has yet to be developed. In this study, we accumulated fouling polysaccharides, purified them by lectin affinity chromatography, and then conducted partial hydrolysis and MALDI-TOF/MS analysis. By comparing the peaks detected by MALDI-TOF/MS analysis with the database, we have enabled estimation of the structure of the polysaccharide and the microorganism from which it originated. We have also succeeded in separating proteins by two-dimensional electrophoresis after purifying the membrane fouling material, enabling the reading of the amino acid sequences of the cut-out spots. It is also possible to estimate the structure and origin of the protein by comparing it with the database.