Abstract：
Extracellular polymeric substances (EPS) are considered to play a pivotal role in shaping granules\' physical properties. In this contribution, we characterized the viscoelastic properties of EPS from granules of 9 full-scale industrial anaerobic reactors; and quantitatively investigated whether these properties correlate with granules\' resistance to compression (Egranule) and shear strength (Sgranule). Most granules with a higher shear strength, also exhibited a stronger resistance to compression (r = 0.96, p = 0.002), except those granules that contained relatively more proteins in their EPS. Interestingly, these granules were also the most resistant to shear stress (Sgranule ≥ 110 ± 40 h). Furthermore, the EPS hydrogels of these granules had slower softening rates (κ < 0.9) compared to the others (κ ranged between 0.95 and 1.20), indicating stronger gels were formed. These findings suggest that the EPS hydrogel softening rate could be a key parameter to explain granule\'s shear strength.
摘要：
胞外聚合物(EPS)被认为在形成颗粒的物理性质中起关键作用。在这一贡献中,我们从9个全规模工业厌氧反应器的颗粒中表征了EPS的粘弹性特性；并定量研究了这些特性是否与颗粒的抗压缩性（Ecandile）和剪切强度（Scandile）相关。大多数颗粒具有较高的剪切强度，还表现出较强的抗压缩性(r=0.96，p=0.002)，除了那些在EPS中含有相对更多蛋白质的颗粒。有趣的是,这些颗粒对剪切应力的抵抗力也最强（颗粒≥110±40h）。此外，这些颗粒的EPS水凝胶的软化速率(κ<0.9)比其他的(κ范围在0.95和1.20之间)更慢,表明形成了更强的凝胶。这些发现表明，EPS水凝胶软化速率可能是解释颗粒剪切强度的关键参数。
