Department of Environmental Engineering and Water Technology, UNESCO-IHE Institute for Water Education, Westvest 7, 2611AX, Delft, The Netherlands; Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, The Netherlands.
Department of Environmental Engineering and Water Technology, UNESCO-IHE Institute for Water Education, Westvest 7, 2611AX, Delft, The Netherlands.
Water Res. 2017 Jun 1;116:53-64. doi: 10.1016/j.watres.2017.03.017. Epub 2017 Mar 7.
Thiothrix caldifontis was the dominant microorganism (with an estimated bio-volume of 65 ± 3%) in a lab-scale enhanced biological phosphorus removal (EBPR) system containing 100 mg of sulphide per litre in the influent. After a gradual exposure to the presence of sulphide, the EBPR system initially dominated by Candidatus Accumulibacter phosphatis Clade I (98 ± 3% bio-volume) (a known polyphosphate accumulating organism, PAO) became enriched with T. caldifontis. Throughout the different operating conditions studied, practically 100% phosphate removal was always achieved. The gradual increase of the sulphide content in the medium (added to the anaerobic stage of the alternating anaerobic-aerobic sequencing batch reactor) and the adjustment of the aerobic hydraulic retention time played a major role in the enrichment of T. caldifontis. T. caldifontis exhibited a mixotrophic metabolism by storing carbon anaerobically as poly-β-hydroxy-alkanoates (PHA) and generating the required energy through the hydrolysis of polyphosphate. PHA was used in the aerobic period as carbon and energy source for growth, polyphosphate, and glycogen formation. Apparently, extra energy was obtained by the initial accumulation of sulphide as an intracellular sulphur, followed by its gradual oxidation to sulphate. The culture enriched with T. caldifontis was able to store approximately 100 mg P/g VSS. This research suggests that T. caldifontis could behave like PAO with a mixotrophic metabolism for phosphorus removal using an intracellular sulphur pool as energy source. These findings can be of major interest for the biological removal of phosphorus from wastewaters with low organic carbon concentrations containing reduced S-compounds like those (pre-)treated in anaerobic systems or from anaerobic sewers.
在实验室规模的强化生物除磷 (EBPR) 系统中，进水含有 100 毫克/升的硫化物，其中优势微生物（生物体积估计为 65 ± 3%）为硫丝菌属（Thiothrix）。在逐渐暴露于硫化物存在的情况下，最初由聚磷菌（PAO）优势菌属的聚磷菌属（Accumulibacter）Clade I（生物体积 98 ± 3%）主导的 EBPR 系统，被硫丝菌属（T. caldifontis）富集。在研究的不同运行条件下，始终实现了几乎 100%的磷酸盐去除。在培养基中逐渐增加硫化物含量（添加到交替缺氧-好氧序批式反应器的缺氧阶段）和调整好氧水力停留时间在硫丝菌属的富集中起着重要作用。硫丝菌属通过在厌氧条件下将碳作为聚-β-羟基-烷酸酯（PHA）储存并通过聚磷酸盐的水解产生所需的能量，表现出混合营养代谢。PHA 在好氧期被用作生长、聚磷酸盐和糖原形成的碳和能源来源。显然，通过最初积累作为细胞内硫的硫化物获得了额外的能量，然后逐渐氧化为硫酸盐。用硫丝菌属富集的培养物能够储存约 100 毫克 P/g VSS。这项研究表明，硫丝菌属可能表现出混合营养代谢，以细胞内硫池作为能量来源，用于去除废水中的磷。这些发现对于从含有低有机碳浓度的废水中去除磷具有重要意义，这些废水含有如厌氧系统或厌氧下水道中预处理的还原 S 化合物。
