Abstract The stoichiometric reactions that characterize protein fermentation during anaerobic wastewater treatment were investigated using bovine serum albumin (BSA) as the model protein. A methodology was developed to describe anaerobic protein degradation to volatile fatty acids (VFAs) using a single reaction step based on the dominant amino acid fermentation pathways. The importance of this work stems from the burgeoning need for resource recovery by production of VFAs from waste activated sludge at municipal wastewater treatment plants. The optimum initial fermentation conditions for BSA degradation to organic acids were first established at a pH of 8 and fermentation time of 3 days. The results from two batch experiments of BSA at concentrations of 2 g/L and 4 g/L showed that the stoichiometric coefficients for acetic, butyric, and valeric acids generally compared very well with the theoretical except for propionic acid which resulted from an alternative fermentation pathway for arginine and proline without propionic acid production. The organic acids produced at each BSA concentration varied respectively by ± 15 % and ± 12 % from the theoretical and the amino acid fermentation pathways remained the same irrespective of concentration differences. The experimental stoichiometric coefficients for iso-butyric and iso-valeric acids were within 10%–15% of the theoretical values, thus validating the use of a single stoichiometry for the overall catabolic reaction of anaerobic protein fermentation to organic acids.

中文翻译：

---

厌氧蛋白质发酵的化学计量

摘要 使用牛血清白蛋白 (BSA) 作为模型蛋白质，研究了表征厌氧废水处理过程中蛋白质发酵的化学计量反应。开发了一种方法来描述使用基于主要氨基酸发酵途径的单一反应步骤将厌氧蛋白质降解为挥发性脂肪酸 (VFA)。这项工作的重要性源于通过城市污水处理厂废弃活性污泥生产 VFA 来回收资源的新兴需求。BSA 降解为有机酸的最佳初始发酵条件首先确定为 pH 值为 8，发酵时间为 3 天。浓度为 2 g/L 和 4 g/L 的 BSA 的两批实验结果表明，乙酸、丁酸、和戊酸通常与理论相比非常好，但丙酸除外，丙酸是由精氨酸和脯氨酸的替代发酵途径产生的，不产生丙酸。在每个 BSA 浓度下产生的有机酸与理论值分别相差 ±15% 和 ±12%，无论浓度差异如何，氨基酸发酵途径都保持相同。异丁酸和异戊酸的实验化学计量系数在理论值的 10%–15% 范围内，从而验证了使用单一化学计量学进行厌氧蛋白质发酵生成有机酸的整体分解代谢反应。