Surface properties of bacteria from activated sludge in relation to bioflocculation  

作　　者：Bing Xie Jidong Gu Jun Lu 

机构地区：[1]Key Laboratory of Urbanization and Ecological Restoration of Shanghai, Department of Environmental Science & Technology, East China Normal University, Shanghai 200062, China [2]Laboratory of Environmental Toxicology, Department of Ecology & Biodiversity, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China [3]Department of Interdisciplinary Studies, Faculty of Health & Environmental Sciences, Auckland University of Technology, Auckland 1142, New Zealand [4]School of Biological Sciences, Faculty of Science, University of Auckland, Auckland 1142, New Zealand

出　　处：《Journal of Environmental Sciences》2010年第12期1840-1845,共6页环境科学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(No. 20977031);the Natural Science Foundation of Shanghai(No. 09zr1409000);the Research Initiatives of the University of Hong Kong(2006);the Royal Society of New Zealand(ISAT B09-33);Faculty of Health & Environmental Sciences,Auckland University of Technology

摘　　要：Two bacterial stains were isolated from the activated sludge and identified as Leucobacter sp. and Alcaligenesfaecalis by 16S rDNA sequencing. Pure cultures of these two strains, representing well or poorly settled bacteria, were used to investigate the mechanism of bioflocculation in activated sludge. Based on the analyses of the characteristics of cells hydrophobicity, ζ-potential, flocculation ability and extracellular polymeric substance （EPS） composition under different growth stages, it was found that the ratio of cell EPS protein had the highly influence on ζ-potential and hydrophobicity, which were important factors to bioflocculation. Cellulase and Proteinase K could destroy the extracellular biopolymer and resulted in a decrease in the hydrophobicity and ζ-potential. However, in our study, the flocculation characteristics exhibited differently in relation to cellulase and Proteinase K. Flocculation of cells treated with cellulase and Proteinase K decreased sharply, and then recovered quickly in cellulase treatment, while cells treated with Proteinase K showed no sign of recovery. This reveals that the presence of protein in extracellular biopolymer plays an important role to the bioflocculation of cells.Two bacterial stains were isolated from the activated sludge and identified as Leucobacter sp. and Alcaligenesfaecalis by 16S rDNA sequencing. Pure cultures of these two strains, representing well or poorly settled bacteria, were used to investigate the mechanism of bioflocculation in activated sludge. Based on the analyses of the characteristics of cells hydrophobicity, ζ-potential, flocculation ability and extracellular polymeric substance （EPS） composition under different growth stages, it was found that the ratio of cell EPS protein had the highly influence on ζ-potential and hydrophobicity, which were important factors to bioflocculation. Cellulase and Proteinase K could destroy the extracellular biopolymer and resulted in a decrease in the hydrophobicity and ζ-potential. However, in our study, the flocculation characteristics exhibited differently in relation to cellulase and Proteinase K. Flocculation of cells treated with cellulase and Proteinase K decreased sharply, and then recovered quickly in cellulase treatment, while cells treated with Proteinase K showed no sign of recovery. This reveals that the presence of protein in extracellular biopolymer plays an important role to the bioflocculation of cells.

关 键 词：activated sludge HYDROPHOBICITY ζ-potential BIOFLOCCULATION pure culture 

分 类 号：Q939.1[生物学—微生物学] X703[环境科学与工程—环境工程]