Jiangxi Province Key Laboratory of Water Ecological Conservation in Headwater Regions (2023SSY02031), Jiangxi University of Science and Technology, Ganzhou, 341000, China.
Jiangxi Province Key Laboratory of Water Ecological Conservation in Headwater Regions (2023SSY02031), Jiangxi University of Science and Technology, Ganzhou, 341000, China; Jiangxi Province Ganzhou key laboratory of Basin pollution simulation and control, Ganzhou, 341000, China.
J Environ Manage. 2024 Nov;370:122828. doi: 10.1016/j.jenvman.2024.122828. Epub 2024 Oct 9.
D-limonene extracted from citrus peels possesses an inhibitory effect on methanogenic archaea. This study is aimed to bridge the research gap on the influence of D-limonene on volatile fatty acids (VFA) production from waste activated sludge (WAS) and to address the low VFA yield in standalone anaerobic fermentation of WAS. When the initial pH was not controlled, 1.00 g/g TSS D-limonene resulted in a VFA accumulation of 1175.45 ± 101.36 mg/L (174.45 ± 8.13 mgCOD/gVS). When the initial pH was controlled at 10 and the D-limonene concentration was 0.50 g/g TSS, the VFA accumulation reached 2707.44 ± 183.65 mg/L (445.51 ± 17.10 mgCOD/gVS). The pH-regulated D-limonene treatment enhanced solubilization and acidification, slightly inhibited hydrolysis, and significantly suppressed methanogenesis. D-limonene under alkaline conditions can increase the relative abundance of Clostridium_sensu_stricto, significantly enhancing acidification. Moreover, it markedly inhibited methanogenesis by particularly reducing the relative abundance of Methanothrix that was responsible for acetate consumption, thus favoring the accumulation of VFA. The research reveals the potential mechanism of pH regulation and D-limonene on anaerobic fermentation acid production, providing a theoretical basis for improving the acid production performance of the anaerobic fermentation of WAS.
从桔皮中提取的 D-苎烯对产甲烷古菌具有抑制作用。本研究旨在填补 D-苎烯对废活性污泥（WAS）产挥发性脂肪酸（VFA）影响的研究空白，并解决 WAS 单独厌氧发酵中 VFA 产率低的问题。当不控制初始 pH 值时，1.00 g/g TSS 的 D-苎烯导致 VFA 积累为 1175.45 ± 101.36 mg/L（174.45 ± 8.13 mgCOD/gVS）。当初始 pH 值控制在 10 且 D-苎烯浓度为 0.50 g/g TSS 时，VFA 积累达到 2707.44 ± 183.65 mg/L（445.51 ± 17.10 mgCOD/gVS）。pH 调节的 D-苎烯处理增强了溶解和酸化，略微抑制了水解，显著抑制了产甲烷作用。碱性条件下的 D-苎烯可以增加 Clostridium_sensu_stricto 的相对丰度，显著增强酸化。此外，它通过特别降低负责乙酸消耗的 Methanothrix 的相对丰度，显著抑制了产甲烷作用，从而有利于 VFA 的积累。该研究揭示了 pH 调节和 D-苎烯对厌氧发酵产酸的潜在机制，为提高 WAS 厌氧发酵产酸性能提供了理论依据。
