The liver can detoxify various metabolites; synthesise proteins and produce biochemicals needed for digestion. Glutathione conjugates to NAPQI and helps to detoxify it. Finally, some microbes have enzymes to detoxify oxygen metabolites formed during the respiratory burst. Animals and humans possess the ability to detoxify cyanide from their systems naturally. Hobbyist aquaria typically do not have the requisite bacteria needed to detoxify nitrogen waste. A different enzyme may detoxify LPS when it enters, or is produced in, animal tissues. The young have a decreased capacity to detoxify chlorpyrifos and its metabolites. Ozone will also detoxify cyanides by converting them to cyanates. These reactions act in concert to detoxify xenobiotics and remove them from cells. McElroy and Seliger proposed 1962 that the bioluminescent reaction evolved to detoxify oxygen. "Beggiatoa" are also able to detoxify hydrogen sulfide in soil. Cassava must be cooked properly to detoxify it before it is eaten. It can detoxify them and even convert them into sex pheromones. Therefore, technologies to detoxify the exhaust are an essential part of emissions control. Luckily, his Time Lord physiology allows him to detoxify.