In general, the biodegradation of a toxic compound by a micro-organism requires the concurrence of, at least, two features in the biological system: first, the capability of the micro-organism to metabolize the toxic compound, and secondly, the capacity to resist its toxic effect. Pseudomonas pseudoalcaligenes CECT5344 is a bacterium used in the biodegradation of cyanide because it is capable to use it as a nitrogen source. The present review is mainly focused on the putative role of iron-containing enzymes of the tricarboxylic acid cycle in cyanide resistance by P. pseudoalcaligenes CECT5344.