Researcher's Profile

Water supply and water treatment in urban cities are supported by microorganisms. For example, biological activated carbon treatment has been introduced to major drinking water treatment plants in Tokyo. Sewage is basically treated by biological activated sludge system. These technologies have been established empirically and have been regarded as a black box because the structures and functions of microbial communities have not been fully elucidated. In order to deepen our understanding of biological treatment and establish efficient operation, molecular biological methods have been applied to characterize the diversity and potential of microorganisms in biological treatment. Our study revealed that novel microorganisms such as complete ammonia oxidizing microorganisms were dominant in biological activated carbon treatment and contributed to ammonia removal.

On the other hand, microorganisms are also a health risk factor for us. Due to population decline and aging of water infrastructure, the regrowth of opportunistic pathogens such as Legionella and nontuberculous mycobacteria in premise plumbing is concerned. We try to elucidate their physiology and ecology to control their regrowth. Antimicrobial-resistant bacteria (ARB) pose a global health threat, which is regarded as silent pandemic. “One Health” approach that integrates humans, livestock, and environment is important to control ARB. In developing countries where sewage treatment is not available, the release of untreated sewage results in the spread of ARB. However, compared to knowledge of ARB in human and livestock sectors, the occurrence and horizontal gene transfer of ARB in the environment remain unknown. Moreover, the surveillance scheme of ARB in the environment has not been established yet. We aim to clarify the behavior of ARB in urban water environments and water systems.

fig.1. Biological activated carbon

fig.2. Metagenomic analysis of antimicrobial resistance genes in water environment