School of Resources and Environment, University of Jinan, Jinan, 250100, China; State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, 3010, Victoria, Australia.
Chemosphere. 2017 Apr;172:286-293. doi: 10.1016/j.chemosphere.2017.01.012. Epub 2017 Jan 5.
Land application of agricultural wastes is considered as a promising bioremediation approach for cleaning up soils contaminated by aged polycyclic aromatic hydrocarbons (PAHs). However, it remains largely unknown about how microbial PAH-degraders, which play a key role in the biodegradation of soil PAHs, respond to the amendments of agricultural wastes. Here, a 90-day soil microcosm study was conducted to compare the effects of three agricultural wastes (i.e. WS, wheat stalk; MCSW, mushroom cultivation substrate waste; and CM, cow manure) on the dissipation of aged PAHs and the abundance and community structure of PAH-degrading microorganisms. The results showed that all the three agricultural wastes accelerated the dissipation of aged PAHs and significantly increased abundances of the bacterial 16S rRNA and PAH-degrading genes (i.e. pdo1 and nah). CM and MCSW with lower ratios of C:N eliminated soil PAHs more efficiently than WS with a high ratio of C:N. Low molecular weight PAHs were dissipated more quickly than those with high molecular weight. Phylogenetic analysis revealed that all of the nah and C12O clones were affiliated within Betaproteobacteria and Gammaproteobacteria, and application of agricultural wastes significantly changed the community structure of the microorganisms harboring nah and C12O genes, particularly in the CM treatment. Taken together, our findings suggest that the three tested agricultural wastes could accelerate the degradation of aged PAHs most likely through changing the abundances and community structure of microbial PAH degraders.
农业废弃物的土地应用被认为是一种很有前途的生物修复方法，可用于清理受老化多环芳烃（PAHs）污染的土壤。然而，对于在土壤 PAHs 生物降解中起关键作用的微生物 PAH 降解菌如何响应农业废弃物的添加，目前还知之甚少。在这里，进行了为期 90 天的土壤微宇宙研究，以比较三种农业废弃物（即 WS，麦秸；MCSW，蘑菇栽培基质废物；和 CM，牛粪）对老化 PAHs 的消解以及 PAH 降解微生物的丰度和群落结构的影响。结果表明，所有三种农业废弃物都加速了老化 PAHs 的消解，并显著增加了细菌 16S rRNA 和 PAH 降解基因（即 pdo1 和 nah）的丰度。C:N 比低的 CM 和 MCSW 比 C:N 比高的 WS 更有效地消除土壤 PAHs。低分子量 PAHs 的消解速度比高分子量的 PAHs 更快。系统发育分析表明，所有 nah 和 C12O 克隆均属于β变形菌纲和γ变形菌纲，农业废弃物的应用显著改变了携带 nah 和 C12O 基因的微生物群落结构，特别是在 CM 处理中。总之，我们的研究结果表明，三种测试的农业废弃物可以通过改变微生物 PAH 降解菌的丰度和群落结构来加速老化 PAHs 的降解。
