细菌对有机污染物的趋化性及其对降解的影响

有机污染的微生物治理被认为是一种安全、有效和经济的治理方式，其生物可利用性是影响生物降解效率的主要限制因子之一。趋化性可以使细菌与污染物紧密接触，提高有机污染物的生物可利用性，从而提高降解效率。本文综述了细菌趋化性的基本概念及趋化信号传导机制，并以环境中典型的有机污染物为例，重点阐述了趋化对降解的影响，以及从细菌对污染物的趋化、降解和转运之间的关系揭示趋化与降解的内在关联。 通讯作者: 沈超峰（http://orcid.org/0000-0002-8576-6712） E-mail: ysxzt@zju.edu.cn
Abstract: The bioremediation of organic pollutants is regarded as a safe, economical and efficient strategy. Nevertheless, biodegradation efficiency is not only associated with the degrading capability of bacteria, but also depends on the bioavailability of pollutants, which is influenced by microbial mobility in addition to the soil medium and nature of the pollutants. On account of the high hydrophobicity, most of the soil organic pollutants are strongly adsorbed to soil and the bioavailability is poor. In the past few years, many studies have shown that most motile bacteria can sense and access pollutants through the process of chemotaxis. The chemotactic movement of bacteria can increase the bioavailability of organic pollutants, which in turn have a beneficial role in bioremediation. Chemotaxis has been extensively studied in Escherichia coli, but the E. coli chemosensory system reflects only a small fraction of the diversity of bacterial chemotactic responses. A limited number of compounds like amino acids, organic acids and sugars are the primary attractants for E. coli. Whereas for many free-living bacteria, a much wider range of attractants have been documented, such as naphthalene, toluene, biphenyl, polychlorinated biphenyls, benzoic acid, chlorobenzoic acids, nitroaromatics, methyl parathion and atrazine. The involved species include Pseudomonas sp., Ralstonia sp., Azospirillum sp., Rhizobium sp., Burkholderia sp. and Arthrobacter sp. At present, there is sufficient evidence indicating that chemotaxis can increase the bioavailability of organic pollutants. The best studied example is the degrading capacity of Pseudomonas putida G7 to naphthalene. In addition, studies about the chemotaxis of Ralstonia sp. SJ98 towards p-nitrophenol and Pseudomonas putida DLL-1 to methyl parathion demonstrated that chemotaxis could enhance in situ bioremediation of soil pollution. The effect of bacterial chemotaxis on degradation implies a significant link between chemotaxis and degradation. Chemotaxis is now only observed towards compounds which can be degraded by the microorganisms, while non-substrate compounds are not found to be chemoattractants. And the observation that specific pollutant chemoreceptors were co-localized with the degradation genes on plasmids combined with the