Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Aalborg, Denmark.
ISME J. 2013 Mar;7(3):543-54. doi: 10.1038/ismej.2012.136. Epub 2012 Nov 22.
Members of the genus Tetrasphaera are considered to be putative polyphosphate accumulating organisms (PAOs) in enhanced biological phosphorus removal (EBPR) from wastewater. Although abundant in Danish full-scale wastewater EBPR plants, how similar their ecophysiology is to 'Candidatus Accumulibacter phosphatis' is unclear, although they may occupy different ecological niches in EBPR communities. The genomes of four Tetrasphaera isolates (T. australiensis, T. japonica, T. elongata and T. jenkinsii) were sequenced and annotated, and the data used to construct metabolic models. These models incorporate central aspects of carbon and phosphorus metabolism critical to understanding their behavior under the alternating anaerobic/aerobic conditions encountered in EBPR systems. Key features of these metabolic pathways were investigated in pure cultures, although poor growth limited their analyses to T. japonica and T. elongata. Based on the models, we propose that under anaerobic conditions the Tetrasphaera-related PAOs take up glucose and ferment this to succinate and other components. They also synthesize glycogen as a storage polymer, using energy generated from the degradation of stored polyphosphate and substrate fermentation. During the aerobic phase, the stored glycogen is catabolized to provide energy for growth and to replenish the intracellular polyphosphate reserves needed for subsequent anaerobic metabolism. They are also able to denitrify. This physiology is markedly different to that displayed by 'Candidatus Accumulibacter phosphatis', and reveals Tetrasphaera populations to be unusual and physiologically versatile PAOs carrying out denitrification, fermentation and polyphosphate accumulation.
四球菌属的成员被认为是强化生物除磷（EBPR）工艺中聚磷酸盐积累菌（PAO）。尽管在丹麦的全规模废水 EBPR 工厂中大量存在，但它们的生理生态与“Candidatus Accumulibacter phosphatis”有多相似尚不清楚，尽管它们可能在 EBPR 群落中占据不同的生态位。四个四球菌属分离株（T. australiensis、T. japonica、T. elongata 和 T. jenkinsii）的基因组进行了测序和注释，并利用这些数据构建了代谢模型。这些模型纳入了在 EBPR 系统中遇到的交替厌氧/好氧条件下理解其行为的关键碳和磷代谢的核心方面。尽管较差的生长限制了它们在纯培养中的分析，但这些代谢途径的关键特征得到了研究。基于这些模型，我们提出在厌氧条件下，与四球菌属相关的 PAO 会吸收葡萄糖并将其发酵为琥珀酸和其他成分。它们还合成糖原作为储存聚合物，利用从储存聚磷酸盐和基质发酵降解中产生的能量。在好氧阶段，储存的糖原被分解以提供能量用于生长，并补充后续厌氧代谢所需的细胞内聚磷酸盐储备。它们还能够进行反硝化。这种生理机能与“Candidatus Accumulibacter phosphatis”显示的生理机能明显不同，表明四球菌属种群是不寻常的、生理上多功能的 PAO，能够进行反硝化、发酵和聚磷酸盐积累。
