Methane Production Reduced by Lignin Derivatives in Pulping Wastewater: Inhibition of Free Hydrolase
Jinxu Lei,
Zhihong Xu,
Yong Chen,
Guo Yu,
Zexiang Liu,
Shuangfei Wang,
Jian Zhang,
Kelin Li,
Li Xie
Affiliations
Jinxu Lei
Guangxi Key Laboratory of Clean Pulp & Papermaking and Pollution Control, College of Light Industry and Food Engineering, Guangxi University, Nanning 530004, China
Zhihong Xu
Guangxi Key Laboratory of Clean Pulp & Papermaking and Pollution Control, College of Light Industry and Food Engineering, Guangxi University, Nanning 530004, China
Yong Chen
Guangxi Key Laboratory of Clean Pulp & Papermaking and Pollution Control, College of Light Industry and Food Engineering, Guangxi University, Nanning 530004, China
Guo Yu
Guangxi Key Laboratory of Clean Pulp & Papermaking and Pollution Control, College of Light Industry and Food Engineering, Guangxi University, Nanning 530004, China
Zexiang Liu
Guangxi Key Laboratory of Clean Pulp & Papermaking and Pollution Control, College of Light Industry and Food Engineering, Guangxi University, Nanning 530004, China
Shuangfei Wang
Guangxi Key Laboratory of Clean Pulp & Papermaking and Pollution Control, College of Light Industry and Food Engineering, Guangxi University, Nanning 530004, China
Jian Zhang
Guangxi Key Laboratory of Clean Pulp & Papermaking and Pollution Control, College of Light Industry and Food Engineering, Guangxi University, Nanning 530004, China
Kelin Li
Guangxi Key Laboratory of Clean Pulp & Papermaking and Pollution Control, College of Light Industry and Food Engineering, Guangxi University, Nanning 530004, China
Li Xie
Guangxi Key Laboratory of Clean Pulp & Papermaking and Pollution Control, College of Light Industry and Food Engineering, Guangxi University, Nanning 530004, China
The lignin derivatives generated during pulping might be responsible for the suboptimal performance of anaerobic reactors during the treatment of pulping wastewater. However, the exact mechanisms by which these derivatives exert influence remain unclear. This study investigated the influence of lignin derivatives, simulated using humic acids (HAs), in anaerobic granular sludge (AnGS). Compared to the enzymes present during floc-bonding and granule-bonding, the HAs impeded the conversion of unhydrolyzed substrates into methane and caused considerable inactivation of free enzymes. Simultaneously, the HAs suppressed agglomeration and weakened the strength of the AnGS. Furthermore, calcium ions helped maintain the integrity of the sludge structure. Therefore, the inhibition of extracellular enzymes using lignin derivatives delays the methanation of unhydrolyzed substrates, resulting in a reduced biomass within AnGS reactors owing to sludge disintegration and biomass loss. This study serves as a reference for investigating the persistent risks originating from lignin derivatives associated with using anaerobic granular-sludge bed reactors to treat pulping wastewater.
