Research Interest
The 21st century is known as aWater Century. Water environmental problems, such as water contamination and watershortage due to population expansion，may increase the risk of human’s infection, and affect our dailylife. In our laboratory, we are making efforts to realize sustainableutilization of water resources. Under this objective, we widely conduct somefundamental and application researches related to water environment.
Fundamental Research of WaterEnvironment
1. Water Contamination Caused byEutrophication
Recently, one of thewater environmental problems has been coming into the public highlight. Thatis, water bloom caused by the over-growth of some specific algae, which maychange the original watercolor into green. Once it occurred in a reservoir,these toxic substances and musty odor compounds may lead to contamination inour drinking water. Although appropriate treatments have been conducted inJapanese Water Purification Plant, situations are quite different in some otherareas, where sufficient treatment cannot be conducted. As reported, these toxicsubstances are metabolites of Cyanobacteria which is one of factors lead towater bloom. On the other hand, musty odor compounds are mainly produced by Cyanobacteria and Actinomycetes that live in the mud.
In our laboratory,experiments have been carried out to clarify the toxicology mechanism of mustyodor compounds, and make a contribution to reserve and improve the waterenvironment.
Bloom eventoccurred at the Kasumigaura Lake (July, 2011)
2. Relationship betweenProkaryotes and Global Warming
Nowadays, the ongoing Global Warming has affected the balance ofEarth’s material circulation. Therefore, researches should focus on not only inatmosphere and continental systems, but also in ocean systems and freshwatersystems, in order to understand an accurate carbon circulation process. Fromsome previous studies, it is known that there are some kinds of bacteria andarchaea that can take in greenhouse gas such as carbon dioxide and methane.
In our laboratory, we take aim at understanding the behavior ofthese bacteria and archaea: how and in what extent do they affect the Earth’smaterial circulation. Sampling regions are mainly Surugawan Bay, Japan, and theArctic Ocean.
Application Researches of WaterEnvironment
1. Water Quality Improvementusing Biofilm Process
Previous researches indicated that mycrocystin (a kind of toxicsubstance), and some musty odor compounds could be degraded by specificmicrobes. Biofilm Process is such a new kind of treatment, which utilizes thenatural degrading ability of specific microbes. Thus, this process is consideredas environmentally friendly water treatment technology.
In our laboratory, we are trying to clarify the biodegradingmechanism of musty odor compounds, and consequently establish better waterpurification systems using bio-techniques.
Honey-comb tube which is used in biofilm process. There aremany biofilm inside Honey-comb tube, and bacteria lived in biofilm conduct watertreatment.
2. Water Quality Improvement using OxygenProductive Electrode
In reservoirs, aeration process is used to maintain the aerobicenvironment in a water system. Nevertheless, the costs of establishment andmaintenance are too high to introduce such equipment in reservoirs.
Our laboratory has been developing new aeration techniques using wateras the raw material to produce oxygen with low-energy consumption.