Microbial transformation of xenobiotics

Introduction The term xenobiotic (Greek xenos + bioticos, which means “strange” and “life-related” respectively) means a chemical substance that is not a natural component of a living organism exposed to it, i.e. a strange, exogenous substance or anthropogenic material. This definition covers substances strange to the target organisms, hence its use for most poisons and drugs. An important group of xenobiotics are chemical compounds produced by humans, with artificial chemical structure, to which organisms have not adjusted through prior evolution [1]. But can we always say with certainty that a given chemical structure cannot be found in the natural environment? One of the key groups of xenobiotics are aromatic compounds with chlorine substituent. At the same time, the Amblyomma americanium tick produces 2,6-dichlorophenol as pheromone and the 2,5-dichlorophenol in the same function was also found in grasshoppers [2]. Therefore, for the microorganisms the xenobiotics are generally defined as all substances with the structure with which the microorganism has had no direct contact during their evolution [1]. It should also be pointed out that not all xenobiotics are necessarily toxic [3]. Due to its structure, strange to the natural microorganism populations, xenobiotics released into the environment can linger there for months or years. However, this does not mean that those substances are never degraded, since not all anthropogenic substances are resistant to microbiological degradation. The horizontal gene transfer and other adaptive processes allow the microorganisms to participate in the transformation of xenobiotics processes.