Produced waste-activated sludge (WAS) can be recovered as a promising carbon source in wastewater treatment plants. However, the cell integrity is always ignored, which results in the unwanted release of N and P. In this work, an alginate-degrading microbial consortium (ADC) with a higher percentage of genus Bacteroides (>90%) was enriched. The role of enriched ADC on the productions of methane and volatile fatty acids (VFAs) and cell integrity (via lactate dehydrogenase (LDH) activity and DNA concentrations) was then investigated in WAS fermentation. The results showed that dosing with ADC increased methane production by 53% without P release. Methane production of 440 mL from extracted extracellular polymeric substances was comparable to that from WAS (445 mL). After inhibiting methanogenesis, VFA concentrations via dosing with ADC were comparable to those of alkali fermentation, while expectantly showing lower N (114 vs 367 mg/L) and P (0 vs 122 mg/L) release. Since N and P are mainly stored within cells, such better selectivity was attributed to the ADC not affecting cell integrity, which was also verified by LDH activity and DNA concentrations. Consequently, these results provide a highly selective microbial method to produce biochemicals from WAS while maintaining cell integrity.

中文翻译：

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藻酸盐降解联合体对废物活化污泥的高选择性发酵

产生的废物活性污泥 (WAS) 可以作为废水处理厂中的一种有前途的碳源进行回收。然而，细胞完整性总是被忽略，这会导致 N 和 P 的有害释放。 在这项工作中，具有较高比例的拟杆菌属的藻酸盐降解微生物聚生体 (ADC)(>90%) 被富集。然后在 WAS 发酵中研究了富集的 ADC 对甲烷和挥发性脂肪酸 (VFA) 产生和细胞完整性（通过乳酸脱氢酶 (LDH) 活性和 DNA 浓度）的作用。结果表明，在不释放磷的情况下，添加 ADC 的甲烷产量增加了 53%。从提取的细胞外聚合物中产生的 440 mL 甲烷与从 WAS (445 mL) 产生的甲烷产量相当。在抑制产甲烷作用后，通过添加 ADC 获得的 VFA 浓度与碱发酵的浓度相当，同时预期显示出较低的 N（114 对 367 mg/L）和 P（0 对 122 mg/L）释放。由于 N 和 P 主要储存在细胞内，这种更好的选择性归因于 ADC 不影响细胞完整性，这也得到了 LDH 活性和 DNA 浓度的验证。