Thauera sp. ZV1C菌株好氧和厌氧降解苯酚的分子机制研究

Ten species with validly published names in the genus Thauera have been isolated from various environments, and these species were reported to be capable of denitrification and aromatic compounds utilization. The Thauera group has been reported to be one of the abundant denigrifiers and plays an important role in COD moving in various wastewater treatment systems. Some Thauera species are capable of degradation aromatic compounds under both aerobic and anaerobic conditions, but related knowledge are limited. A heterotrophic bacterial strain ZV1C capable of aromatic compounds degradation in both aerobic and anaerobic conditions was isolated as a pure culture from a wastewater treatment system recently. The taxonomic position of this isolate within the genus of the Thauera was determined by 16S rDNA sequence analysis. In this project, we try to analysis the phenol degradation in strain ZV1C under aerobic and anaerobic conditions by using UPLC, HPLC-QTofMS, two-dimensional electrophoresis and RT-PCR method. We expect to find out the molecular mechanisms of both the aerobic and anaerobic phenol degradation pathways in this strain, which hoped be help for wastewater treatment system improvement.

Thauera属是一类具有反硝化和芳香族化合物降解能力的菌株，目前已经分离并鉴定的只有10个种。该属菌株是各种污水处理系统中重要的反硝化和COD去除微生物，并且该属某些菌株可以同时在好氧和厌氧条件下降解芳香族化合物，然而目前对该属芳香族化合物好氧降解途径的研究还未见报导。在前期工作中，从某废水处理系统中分离发现一株异养、兼性厌氧细菌Thauara sp. ZV1C，可以分别在好氧和厌氧条件下降解苯酚和香兰素等芳香族化合物。本项目拟利用UPLC、HPLC-QTofMS、蛋白质二维电泳和反转录荧光定量PCR等方法，分别鉴定苯酚好氧和厌氧代谢的中间产物,分别在好氧和厌氧条件下，比较该菌株葡萄糖和苯酚代谢差异表达的蛋白和基因，揭示该菌株苯酚好氧和厌氧降解的分子机制，为污水处理技术和系统的改进、优化提供理论基础和技术支持。

Thauera属是一类有反硝化和芳香族合物降解能力的菌株，研究证明该属菌株是各污水处理系统中重要的反硝化和COD去除微去除微生物，并且该属许多菌株可以同时在好氧和厌条件下降解芳香族化合物。本研究从废水处理系统中分离纯化到一株Thauera新种菌株ZV1C，利用多相分类方法和全基因组测序等方法对该菌株进行了鉴定，并命名为Thauera phenolivorans。菌株ZV1C基因组大小为3.68Mb，GC含量为68.21%。14个Scaffold，128个cotig。预测编码基因3445个。菌株ZV1C全基因组数据提交至GenBank数据库，序列号为MBFM00000000。通过该菌株的全基因组数据、该菌株在好氧和厌氧条件下的差异蛋白和苯酚降解的中间产物，推测出两种情况下苯酚可能的降解途径。在好氧条件下，苯酚在苯酚羟化酶和邻苯二酚2，3-双加氧酶的作用下通过间位开环途径进行降解，中间产物检测到邻苯二酚，差异蛋白检测到苯酚单加氧酶和邻苯二酚2，3双加氧酶等间位开环途径相关酶，发现菌株ZV1C基因组中有两个参与苯酚降解的基因簇ZV1CGM000666-672和ZV1CGM001734-1740，苯酚羟化酶为6组分寡聚蛋白；在厌氧条件下，苯酚的降解可能有羧基裂合酶、甲基转移酶、铁氧还蛋白等蛋白的参与，并且可能有苯醌衍生物的中间产物产生，而氧化还原反应的电子受体很可能是二硫化物。实验结果为Thauera菌株厌氧芳烃代谢研究提供了基础数据，为污水生物处理系统的发展和生物处理技术的优化提供了理论基础。