Guangdong Provincial Key Laboratory of Petrochemical Pollution Process and Control, School of Environmental Science and Engineering, Guangdong University of Petrochemical Technology, Maoming 525000, PR China.
School of Environment and Safety Engineering, North University of China, Taiyuan 030051, PR China.
Ecotoxicol Environ Saf. 2021 Apr 1;212:111970. doi: 10.1016/j.ecoenv.2021.111970. Epub 2021 Jan 28.
In this study, a taxonomic and functional metagenomic method was used to investigate the difference produced between degrading bacteria immobilized in layer-by-layer assembly (LBL) microcapsules or not during the bioremediation of a soil polluted with phenanthrene (PHE). Bioaugmentation with LBL microcapsule immobilized degrading bacteria could result in different changes of native microbial communities, shifting the functional gene constructions of polluted soils. The LBL treatment enhanced PHE degradation (initial concentration of 100 mg kg dry soil) by 60% after 25 d compared to the free bacteria (FB). The enhancing effect of PHE degradation produced by the LBL treatment was found to be significantly associated with some crucial phyla (e.g., Bacteroides, Gemmatimonadetes and Acidobacteria) and genera including Streptomyces, Ramlibacter, Mycobacterium, Phycicoccus, Gemmatirosa, Flavisolibacter, Micromonospora, Acid_Candidatus_Koribacter and Gemmatimonas. The main differences of functional metagenomics between LBL and FB treatments were observed in higher levels in metabolism of aromatic hydrocarbons and its related functions or enzymes in the former, e.g., membrane transport systems, binding, substrate transporter, cleavage enzymes, dehydrogenation, oxidase, esterase and glycosidase, greatly favoring PHE mineralization. Therefore, our results provide useful findings on understanding of how immobilization strategies can influence the taxonomic and functional gene composition in soils, as well as polycyclic aromatic hydrocarbons (PAH) degradation.
在这项研究中，采用分类和功能宏基因组学方法研究了在生物修复被菲污染的土壤过程中，固定在层层组装（LBL）微胶囊内的降解细菌与未固定的降解细菌之间产生的差异。通过生物增强作用，LBL 微胶囊固定的降解细菌可能导致土著微生物群落发生不同的变化，改变污染土壤的功能基因结构。与自由细菌（FB）相比，LBL 处理在 25 天后可将 PHE 的降解率提高 60%（初始浓度为 100mgkg 干土）。发现 LBL 处理对 PHE 降解的增强作用与一些关键的门（例如拟杆菌门、芽单胞菌门和酸杆菌门）和包括链霉菌属、拉曼杆菌属、分枝杆菌属、Phycicoccus 属、Gemmatirosa 属、Flavisolibacter 属、Micromonospora 属、 Acid_Candidatus_Koribacter 和 Gemmatimonas 属在内的一些关键属有关。LBL 和 FB 处理之间的功能宏基因组学的主要差异在于前者在芳香烃代谢及其相关功能或酶方面的水平更高，例如膜转运系统、结合、底物转运蛋白、裂解酶、脱氢酶、氧化酶、酯酶和糖苷酶，这极大地有利于 PHE 的矿化。因此，我们的研究结果为了解固定化策略如何影响土壤中的分类和功能基因组成以及多环芳烃（PAH）降解提供了有用的发现。
