Thermo-electric generator which is intended to be immersed in a fluid which contains at least one chemical species, comprising two electrodes each having a first end and a second end, the first ends being connected to each other, the generator being configured to generate an electrical voltage between the two ends when a temperature difference is imposed between each first end and the corresponding second end, the temperature difference being such that one end, referred to as the “hot end”, of each electrode has a temperature which is strictly greater than the temperature of the other end. The hot end of at least one electrode comprises a micro-organism or an enzyme which is capable of causing at least one exothermic reaction involving the chemical species.