The commingled microbial moiety of oxygenic photogranules (OPGs) facilitates aeration-free wastewater treatment. Embedded in an extracellular polymeric substances (EPS) matrix, microbial producers and consumers of oxygen occupying granular niches exchange substrates among themselves and with the bulk fluid. An assessment of the OPG’s phototrophic potential or functional capacity may require combining different photoactivity signals. The photosynthetic capacity was evaluated using photosynthetic oxygen evolution (POE) and chlorophyll fluorescence (rapid light curves, RLC) measurements using OPGs grown at different light intensities.. A maximum oxygen generating capacity for optimal OPGs and reactor conditions was determined to be 284.4 mg_O2 g_VSS^–1 h^–1 The OPGs exhibited photoelasticity, with higher photosynthetic capacity in high light (HL) compared to that in low light (LL) adapted samples. Saturation irradiances before the onset of photoinhibition for LL and HL samples were 1000 and 1200 μmol m^–2 s^–1, respectively using POE signals, and 478 μmol m^–2 s^–1 and 611 μmol m^–2 s^–1 using RLC signals. Moreover, HL adapted samples had higher nonphotochemical quenching rates which allude to the OPG’s photoelastic potential. The correlation coefficients (κ) between POE and RLCs were lower than reported values for pure microbial cultures reflecting the enhanced contribution from different photosynthetic clades with a variety of light-harvesting pigments present in OPGs. In an OPG reactor, the photochemical activity can be influenced by the granular size, granular ecology, and reactor operation metrics related to irradiance interactions such as mixing, self-shading, light intensity, photoperiods, and reactor depth. This presents opportunities for design of intensive wastewater resource recovery using phototrophic granular biomass.

中文翻译：

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脉冲幅度调制和光养-辐照度曲线对产氧光颗粒光合能力的体内评价

含氧光颗粒（OPG）的混合微生物部分有助于无曝气废水的处理。嵌入到细胞外聚合物质（EPS）基质中的微生物生产者和氧气消耗者，占据颗粒状壁ches之间相互交换基质，并与大量流体交换基质。评估OPG的光养潜力或功能能力可能需要组合不同的光活性信号。使用在不同光强度下生长的OPG，通过光合作用的氧气释放（POE）和叶绿素荧光（快速光曲线，RLC）测量来评估光合能力。确定最佳OPG和反应器条件的最大产氧能力为284.4 mg _{O 2} g _VSS ^–1小时^–1 OPG具有光弹性，在高光（HL）下的光合能力高于低光（LL）适应的样品。使用POE信号分别对LL和HL样品进行光抑制之前的饱和辐照度分别为1000和1200μmolm ^–2 s ^–1，以及478μmolm ^–2 s ^–1和611μmolm ^–2 s ^–1使用RLC信号。此外，经HL适应的样品具有更高的非光化学猝灭速率，这暗示了OPG的光弹性潜力。POE和RLC之间的相关系数（κ）低于纯微生物培养物的报告值，反映出OPG中存在各种光捕获色素的情况下，不同光合进化枝的贡献增加。在OPG反应器中，光化学活性可能受粒度，颗粒生态和与辐照度相互作用相关的反应器运行指标的影响，例如混合，自遮蔽，光强度，光周期和反应器深度。这为利用光养性颗粒生物质设计密集的废水资源回收提供了机会。