我国南北区域城市污水处理系统内真菌群落的差异

Differences of fungal community in wastewater treatment plants between south and north China

摘要:

【背景】微生物是污水处理系统内污染物去除的主体，真菌作为其中不可或缺的一部分，在去除有毒化合物、提高生物转化等方面发挥着重要作用，应引起人们的关注。【目的】明确我国南北区域城市污水处理系统内真菌群落的多样性、组成差异及其影响因素。【方法】采集我国北方23个污水处理厂的90份活性污泥样品和南方37个污水处理厂的121份活性污泥样品，提取上述样本的总DNA，并应用Illumina MiSeq平台进行ITS高通量测序，结合多种数量生态学分析方法对数据进行分析。【结果】我国南北区域城市污水处理系统内真菌群落结构存在显著差异，真菌群落多样性南方显著高于北方；我国南北区域真菌群落的组成差异显著，南方群落以Sordariomycetes和Glomeromycetes为优势菌纲，以Ophiocordycep和Alternaria为优势菌属，北方群落以Tremellomycetes和Saccharomycetes为优势菌纲，以Trichosporon和Saccharomyces为优势菌属，其中Tremellomycetes和Sordariomycetes是常见的病原菌，对下游生物或者人类的健康具有潜在威胁，Trichosporon属的丝状真菌若大量异常增殖会引发污泥膨胀现象，影响系统的稳定运行；地理纬度、年平均气温、进水NH4+浓度、进水总氮浓度是导致我国南北区域真菌群落存在差异的重要影响因子。【结论】我国南北区域真菌群落多样性、组成存在显著差异，地理因素、所在城市的气候因素和进水污染物浓度对真菌群落结构影响显著。针对南北区域，应合理调控相应区域内的重要功能菌群，以调控污水处理厂的高效稳定运行，同时密切关注其中的条件致病菌和易引发污泥膨胀的菌群，建立面向种群的优化控制系统以管控风险。

Abstract:

[Background] Microorganisms are main agents to remove pollutants in activated sludge (AS) in wastewater treatment plants (WWTPs), among them, fungi should be paid attention to as they play important roles in removing toxic compounds and improving biological transformation, etc. [Objective] The major research will be focus on to characterize and compare the diversity, composition of fungal communities in WWTPs located in north and south China, determine the influence factors of fungal community structure. [Methods] Ninety AS samples from 23 WWTPs in north China and 121 AS samples from 37 WWTPs in south China were collected, respectively. After DNA extraction and amplification, high-throughput sequencing of ITS gene was carried out using Illumina MiSeq platform. Data were processed by a variety of quantitative ecological analysis methods. [Results] Fungal community structures in AS system between north and south China were significantly different. Diversity of fungal community in south China was higher than that of north China. The dominant classes and genera in fungal community were Sordariomycetes and Glomeromycetes classes, and Ophiocordycep and Alternaria genera in south China. While they were Tremellomycetes and Saccharomycetes classes, and Trichosporon and Saccharomyces genera in north China. Members of the classes Tremellomycetes and Sodariomycetes are opportunistic pathogens, which may be potential threats to downstream organisms or human health. Abnormal growth of members in Trichosporon genus will cause sludge bulking and affect the stable operation of WWTPs. Latitude, annual average air temperature, concentration of NH4+ and the total nitrogen in influent were identified as the important factors that influence fungal community structure in WWTPs. [Conclusion] Fungal communities between north and south China were significantly different in diversity and composition as a results of geographic factors, climate factors and concentration of pollutants in influent. Accordingly, toward the efficient and stable operation of the treatment plants, it is necessary to regulate the different important communities in south and north China. Furthermore, we should pay close attention to the opportunistic pathogenic fungi and some agents that easily cause sludge bulking. Establishment of population-oriented optimal control system is necessary to control the risks.