Enzyme activities in activated sludge flocs.
This study quantified the activities of enzymes in extracellular polymeric substances (EPS) and in pellets. Seven commonly adopted extraction schemes were utilized to extract from aerobic flocs the contained EPS, which were further categorized into loosely bound (LB) and tightly bound (TB) fractions. Ultrasonication effectively extracted the EPS from sludge flocs. Enzyme assay tests showed that the protease activity was localized mainly on the pellets, alpha-amylase and alpha-glucosidase activities were largely bound with LB-EPS, and few protease, alpha-amylase, or alpha-glucosidase activities were associated with the TB-EPS fraction. There exists no correlation between the biochemical compositions of EPS and the distribution of enzyme activities in the sludge matrix. The 44-65% of alpha-amylase and 59-100% of alpha-glucosidase activities noted with the LB-EPS indicate heterogeneous hydrolysis patterns in the sludge flocs with proteins and carbohydrates.
Yu
Guang-Hui
GH
State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze River Water Environment, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, People's Republic of China.
He
Pin-Jing
PJ
Shao
Li-Ming
LM
Lee
Duu-Jong
DJ
D000681:Amylases / Q000032:analysis*; D001673:Biodegradation, Environmental; D005959:Glucosidases / Q000032:analysis*; D010447:Peptide Hydrolases / Q000032:analysis*; D012722:Sewage / Q000032:analysis* / Q000382:microbiology*; D014865:Waste Disposal, Fluid
D012722:Sewage; D000681:Amylases; D005959:Glucosidases; D010447:Peptide Hydrolases