百乐克(BIOLAK)活性污泥宏基因组的生物多样性及功能分析

Biodiversity and Function Analyses of BIOLAK Activated Sludge Metagenome

百乐克(BIOLAK)是一种在全球范围内得到成功推广的多级活性污泥工艺,然而,迄今对于百乐克工艺的核心元件——活性污泥的生物群落及其功能尚鲜见报道.以连云港市大浦工业区废水处理厂为例,借助于新一代高通量测序技术,获得百乐克活性污泥中大规模的宏基因组数据(428 588条高质量DNA序列).鉴定出47个门类、872个属及1 351个物种.细菌域(289 933条序列)中包含33个门,其中变形菌门Proteobacteria是生物量最丰富的门(62.54%),其次是拟杆菌门Bacteroidetes(11.29%)、硝化螺旋菌门Nitrospirae(5.65%)和浮霉菌门Planctomycetes(4.79%),显示这些生物类群在百乐克废水处理系统中发挥着关键作用.在748个细菌属中,硝化螺菌属Nitrospira(5.60%)最为丰富,为活性污泥氮循环过程中的关键菌群.其次为芽单胞菌属Gemmatimonas(2.45%),是生物除磷过程的重要菌属.在古菌域(1 019条序列)中鉴定出3个门及39个属.在真核域(1 055序列),鉴定出10个门及60个属,其中,纤毛虫门Ciliophora是最大的门(257条序列).同时,检测到448条病毒序列,主要为噬菌体.在百乐克活性污泥中,参与氮、芳香化合物和磷代谢的功能基因比例分别为2.50%、2.28%和1.56%,均高于美国和澳大利亚两个废水处理厂活性污泥中功能基因的比例.在氮代谢的4个过程中,反硝化相关基因所占比重最高,达到80.81%,其次是氨化(12.78%)、硝化(4.38%)和固氮(2.04%).总之,在百乐克活性污泥中蕴藏着惊人的生物多样性,同时,参与氮、芳香化合物和磷代谢的功能基因非常丰富.

The BIOLAK is a multi-stage activated sludge process, which has been successfully promoted worldwide. However, the biological community and function of the BIOLAK activated sludge (the core component in the process) have not been reported so far. In this study, taking Lianyungang Dapu Industrial Zone WWTP as an example, a large-scale metagenomic data (428 588 high-quality DNA sequences) of the BIOLAK activated sludge were obtained by means of a new generation of high-throughput sequencing technology. Amazing biodiversity was revealed in the BIOLAK activated sludge, which included 47 phyla, 872 genera and 1 351 species. There were 33 phyla identified in the Bacteria domain (289 933 sequences). Proteobacteria was the most abundant phylum (62. 54% ), followed by Bacteroidetes (11. 29% ), Nitrospirae (5. 65% ) and Planctomycetes (4. 79% ), suggesting that these groups played a key role in the BIOLAK wastewater treatment system. Among the 748 bacterial genera, Nitrospira (5. 60% ) was the most prevalent genus, which was a key group in the nitrogen cycle. Followed by Gemmatimonas (2. 45% ), which was an important genus in the biological phosphorus removal process. In Archaea domain (1 019 sequences), three phyla and 39 genera were detected. In Eukaryota domain (1 055 sequences), 60 genera and 10 phyla were identified, among which Ciliophora was the largest phylum (257 sequences). Meanwhile, 448 viral sequences were detected in the BIOLAK sludge metagenome, which were dominated by bacteriophages. The proportions of nitrogen, aromatic compounds and phosphorus metabolism in the BIOLAK sludge were 2. 50% , 2. 28% and 1. 56% , respectively, which were higher than those in the sludge of United States and Australia. Among four processes of nitrogen metabolism, denitrification-related genes were most abundant ( 80. 81% ), followed by ammonification ( 12. 78% ), nitrification (4. 38% ) and nitrogen fixation (2. 04% ). In conclusion, the BIOLAK activated sludge had amazing biodiversity, meanwhile, functional genes involved in nitrogen, aromatic compounds and phosphorus metabolism were very abundant.