The properties of deep-sea piezophilic bacteria and their possible uses in biotechnology

Bacteria inhabit virtually all of Earth's high pressure oceanic environments. The deep oceanic habitats are at pressures as high as similar to 109 MPa and at temperatures between -0.5 and similar to 113 degrees C. The study of bacteria from these environments gives an idea of how pressure, p, and temperature, T, as coordinate variables affect bacterial adaptation and evolution. The comparison of the growth kinetics of bacteria from the cold deep sea (2 degrees C), from the abyssal Sulu Sea (9.8 degrees C), and from the abyssal Mediterranean Sea (13.5 degrees C) shows the interplay of habitat temperature and pressure to set the response of an organism. The traditional definition of barophily is profitably replaced with one of piezophily which is operationally defined with the aid of a plot of the growth rate constant, k, as a function of T and p. Such a plot, called a pTk diagram, also provides quantitative relationships between growth characteristics of an organism and its habitat. The relationships, furthermore, allow for an otherwise difficult comparison of organisms from different pr habitats. These diagrams may also help in the selection of bacteria with properties appropriate for particular biotechnological applications.