Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA.
Appl Microbiol Biotechnol. 2010 Mar;86(2):435-44. doi: 10.1007/s00253-010-2454-1. Epub 2010 Feb 10.
The process of nitrification has the potential for the in situ bioremediation of halogenated compounds provided a number of challenges can be overcome. In nitrification, the microbial process where ammonia is oxidized to nitrate, ammonia-oxidizing bacteria (AOB) are key players and are capable of carrying out the biodegradation of recalcitrant halogenated compounds. Through industrial uses, halogenated compounds often find their way into wastewater, contaminating the environment and bodies of water that supply drinking water. In the reclamation of wastewater, halogenated compounds can be degraded by AOB but can also be detrimental to the process of nitrification. This minireview considers the ability of AOB to carry out cometabolism of halogenated compounds and the consequent inhibition of nitrification. Possible cometabolism monitoring methods that were derived from current information about AOB genomes are also discussed. AOB expression microarrays have detected mRNA of genes that are expressed at higher levels during stress and are deemed "sentinel" genes. Promoters of selected "sentinel" genes have been cloned and used to drive the expression of gene-reporter constructs. The latter are being tested as early warning biosensors of cometabolism-induced damage in Nitrosomonas europaea with promising results. These and other biosensors may help to preserve the tenuous balance that exists when nitrification occurs in waste streams containing alternative AOB substrates such as halogenated hydrocarbons.
硝化作用的过程有可能实现原位生物修复卤代化合物，只要克服一些挑战即可。在硝化作用中，氨被氧化为硝酸盐的微生物过程中，氨氧化细菌（AOB）是关键角色，能够进行难生物降解的卤代化合物的生物降解。通过工业用途，卤代化合物经常进入废水，污染环境和供水的水体。在废水的回收利用中，AOB 可以降解卤代化合物，但也会对硝化作用过程产生不利影响。这篇小综述考虑了 AOB 进行卤代化合物共代谢的能力，以及由此产生的硝化作用抑制。还讨论了可能的共代谢监测方法，这些方法源自当前关于 AOB 基因组的信息。AOB 表达微阵列检测到在应激条件下表达水平更高的基因的 mRNA，这些基因被认为是“哨兵”基因。选定的“哨兵”基因的启动子已被克隆，并用于驱动基因报告构建体的表达。后者正在作为早期预警生物传感器进行测试，用于监测硝化作用过程中，在含有替代 AOB 底物（如卤代烃）的废水中产生的共代谢诱导损伤，结果有前景。这些和其他生物传感器可能有助于在含有替代 AOB 底物（如卤代烃）的废水中发生硝化作用时，维持脆弱的平衡。
