Method for labeling biopolymers using isotopes

The invention relates to a novel method for the in-vivo labeling of biopolymers such as proteins, nucleic acids, lipids, carbohydrates and biodegradable plastic using isotopes, especially stabile isotopes. The invention also relates to the use of chemolithotrophic bacteria for the in-vivo isotopic labeling of biopolymers. In particular, the invention relates to the use of CO2-fixing bacteria, such as Ralstonia eurtropha and related methanogenic bacteria for the in-vivo isotopic labeling, especially for labeling using the stable isotope <13>C alone and in combination with other isotopes. In addition, the invention relates to the use of isotropically labeled biomolecules in therapeutic and diagnostic applications, especially in spectroscopic methods and generally as tracers.