Department of Dermatology, Second Xiangya Hospital, Central South University, Changsha 410011, PR China; College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
Department of Dermatology, Second Xiangya Hospital, Central South University, Changsha 410011, PR China.
Water Res. 2022 Apr 1;212:118082. doi: 10.1016/j.watres.2022.118082. Epub 2022 Jan 17.
Lignin, a biological resource with great potential, can be as high as ∼16% of the total organics in the waste activated sludge (WAS). This work therefore aims to fill the knowledge gap about the effect of lignin on short-chain fatty acids (SCFAs) production from anaerobic fermentation of sludge. Experimental results showed that lignin promoted rather than inhibited SCFAs production. Specifically, the presence of 15% lignin promoted the SCFAs production from 129.1 ± 6.5 to 223.14 ± 7.8 mg COD/g VSS compared with the control, and the proportion of acetic increased by 61.8%, while that of propionic decreased by 44.9%. Mechanism exploration revealed that lignin improved the solubilization of biodegradable substrates due to its hydrophobic characteristics. In addition, lignin enhanced the acidogenesis process, possibly by perfecting the electron transfer chain in the fermentation system, and the quinone structure in lignin may compete electrons with methanogens to inhibit the consumption of SCFAs. Microbiological analysis showed that the abundance of microorganisms related to acidogenesi, especially the acetogenesis, including Proteiniclasticum sp., Acetoanaerobium sp., in the fermenter with lignin increased, which caused the community to shift towards specialized and diverse SCFAs production.
木质素是一种具有巨大潜力的生物资源，其在废活性污泥（WAS）中的总有机物含量可高达约 16%。因此，这项工作旨在填补关于木质素对污泥厌氧发酵产生短链脂肪酸（SCFAs）的影响的知识空白。实验结果表明，木质素促进了而不是抑制了 SCFAs 的产生。具体来说，与对照相比，添加 15%的木质素将 SCFAs 的产量从 129.1 ± 6.5 增加到 223.14 ± 7.8 mg COD/g VSS，乙酸的比例增加了 61.8%，而丙酸的比例降低了 44.9%。机制探索表明，木质素由于其疏水性特征提高了可生物降解底物的溶解能力。此外，木质素增强了产酸过程，可能通过完善发酵系统中的电子传递链，并且木质素中的醌结构可能与产甲烷菌争夺电子以抑制 SCFAs 的消耗。微生物分析表明，木质素存在于发酵器中与产酸菌相关的微生物丰度增加，特别是蛋白水解菌属（Proteiniclasticum sp.）和乙酸菌属（Acetoanaerobium sp.），导致群落向专门化和多样化的 SCFAs 生产方向转变。
