CRETUS Institute, Department of Chemical Engineering, Universidade de Santiago de Compostela, 15782, Santiago de Compostela, Spain.
CRETUS Institute, Department of Chemical Engineering, Universidade de Santiago de Compostela, 15782, Santiago de Compostela, Spain.
Water Res. 2020 Sep 15;183:115958. doi: 10.1016/j.watres.2020.115958. Epub 2020 Jun 20.
The valorisation of protein-rich residual streams by anaerobic mixed-culture fermentation (MCF) has been barely studied in contrast to carbohydrate-rich wastes. The aim of this work was, therefore, to investigate how protein composition, i.e. the amino acid (AA) profile, affects the individual consumption of amino acids and, consequently, the outcome of the process. Mixed-culture fermentations were performed with two model proteins (casein and gelatin) using continuous and batch reactors at neutral pH values and 25 °C. The acidification was incomplete for both proteins, with casein achieving a higher value than gelatin. Albeit dominated by acetic acid, product spectra were different as well, with n-butyric acid as the second major product for casein and propionic acid for gelatin. The preferential consumption of amino acids was demonstrated, which interestingly depends on protein composition. The previously accepted stoichiometry accurately describes iso and n-butyric acid production, but it fails for propionic, iso and n-valeric acid generation. Overall, this study offers a better understanding of protein fermentation mechanisms, which will help to improve degradation models and to design fermentation processes, based on optimal substrate selection.
与富含碳水化合物的废物相比，富含蛋白质的剩余物流的厌氧混合培养发酵（MCF）的增值作用几乎没有得到研究。因此，本工作的目的是研究蛋白质组成（即氨基酸（AA）谱）如何影响氨基酸的个体消耗，从而影响该过程的结果。使用两种模型蛋白质（酪蛋白和明胶）在中性 pH 值和 25°C 下使用连续和间歇反应器进行混合培养发酵。两种蛋白质的酸化都不完全，其中酪蛋白的产酸值高于明胶。尽管以乙酸为主，但产物谱也不同，酪蛋白的第二大产物是正丁酸，而明胶的第二大产物是丙酸。证明了氨基酸的优先消耗，这有趣地取决于蛋白质的组成。先前接受的化学计量准确地描述了异丁酸和正丁酸的生成，但对于丙酸、异丁酸和正戊酸的生成则不适用。总的来说，这项研究更好地理解了蛋白质发酵机制，这将有助于改进降解模型，并根据最佳底物选择设计发酵过程。
