Central metabolism of organisms has been subjected to intensive studies, and a number of the enzymes and metabolic functions are used to biotechnological applications. However, many pathways and enzymatic features still remain unknown even in microbial central metabolism. Our studies on a thermophilic bacterium, which is located on the deepest branch of the bacterial phylogenetic tree, found unique and novel features in the central carbon and nitrogen metabolism of this microbe. I will also discuss insights into the evolution of life provided by the clarified features, in the former part of this seminar. In the latter part, I will talk about the application of the microbial metabolism to biotechnological use, especially biosensing technology. Selective assays for amino acids have been developed by combining enzymes and chemicals to mimic and reconstitute physiological reactions.