title: Hydrophilicity/hydrophobicity of anaerobic granular sludge surface and their causes: An in situ research.
abstract: The pursuit of high-rate anaerobic reactor has powerfully promoted the studies of anaerobic granular sludge (AnGS) recently. In this work, Methylene Blue and Rhodamine B were used as hydrophilic/hydrophobic indicators to investigate the hydrophilicity/hydrophobicity of AnGS, and several analysis methods were applied to reveal the causes of difference in hydrophilicity/hydrophobicity between the surface and interior of AnGS. Results showed that hydrophilic/hydrophobic surface area ratios for intact and loose AnGS were 1.587 and 1.207, respectively, indicating that the surface was more hydrophilic than the interior. Such difference was ascribed to spatial distribution discrepancy of polysaccharides and proteins of extracellular polymeric substance. The different relative contents of polar groups like -OH, CO, -NH2 and nonpolar groups like side chains of aromatic amino acids were suggested to be the primary causes that lead to the difference. The results are meaningful for the cultivation of high-activity AnGS and the development of anaerobic technology.
authors: Department of Environmental Engineering, Zhejiang University, Hangzhou, China.
authors: Yiyu
authors: Y
authors: Li
authors: Department of Environmental Engineering, Zhejiang University, Hangzhou, China. Electronic address: pzheng@zju.edu.cn.
authors: Ping
authors: P
authors: Zheng
authors: Department of Environmental Engineering, Zhejiang University, Hangzhou, China.
authors: Meng
authors: M
authors: Zhang
authors: Department of Environmental Engineering, Zhejiang University, Hangzhou, China.
authors: Zhuo
authors: Z
authors: Zeng
authors: Department of Environmental Engineering, Zhejiang University, Hangzhou, China.
authors: Zhiyao
authors: Z
authors: Wang
authors: Department of Environmental Engineering, Zhejiang University, Hangzhou, China.
authors: Aqiang
authors: A
authors: Ding
authors: Department of Environmental Science, Zhejiang University, Hangzhou, China.
authors: Keke
authors: K
authors: Ding
mesh_terms: D001421:Bacteria, Anaerobic / Q000502:physiology*; D019149:Bioreactors / Q000382:microbiology*; D055598:Chemical Phenomena; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*
chemical_list: D012722:Sewage
keywords: Anaerobic granular sludge; Hydrophilicity/hydrophobicity difference; Polar/nonpolar groups ratio; Polysaccharides/proteins ratio