I am interested in mechanisms of life. Currently, genomic structures of more than 500 organisms have been determined, and studies of the life mechanisms have accelerated. Experimental identification of essential genes has been carried out some model organisms, for example Escherichia coli, Bacillus subtilis, and Saccharomyces cerevisiae, and identification of the minimal gene set and clarification of the functions of these genes are in progress to understand the mechanisms of life. Besides, we have applied many bacteria for health care, industry and so on, and have got so many various benefits. Then, I study to apply the strategies and technics used for model organisms to the useful bacteria, to understand such organisms and to utilize them efficiently. On the other hand, I am interested in microbial ecology, too. While more than 99% of bacteria are said to be difficult to cultivate, we have already got many benefits from culturable bacteria. If we find ways to cultivate such uncultured bacteria, we could utilize more abundant bacterial and genetic resources. Then, I focus on air component, and study effects of carbon dioxide concentration on bacterial cultivation.