The microorganisms and their enzymes have been played pivotal roles and an infinite of possibility in biotechnology and the related fields. Today, they are applied to the various fields including the manufacturing of foods and medicines, the development of medical equipment and the environmental cleaning. Our laboratory is focusing to characterization and functional analyses as to the microbes and enzymes related to the fermented foods and extreme environments such as high temperature, acidic, and alkaline conditions. In particular, we have been studying D-amino acid metabolism and function of lactic acid bacteria and other food microorganisms, and the molecular characterization of the related enzymes and their application to bioreactors and biosensors. We are also carrying out the analyses and synthesis of specific food components such as amino acids, amines, and the related analogs, the functional analyses of D-amino acids bound in food proteins and the finding and application of thermophilic bacteriophages and their enzymes.