Direct extractions of proteins to monitor an activated sludge system on a weekly basis for 34 weeks using SDS-page

The diversity and dynamics of microbial communities of phosphorus-removing and non-phosphorus-activated sludge systems have mostly been analysed by cu lture-dependent methods. A more direct method is the isolation of the total protein content of samples of activated sludge systems and separating the proteins with SDS-polyacrylamide gel electrophoresis (SDS-PAGE). Total prot eins were analysed and used as fingerprints to type and compare the diversi ty of the bacterial community. The objectives of this study were to determi ne if there were any differences between the anaerobic anoxic and aerobic z ones of an activated sludge plant as well as the effect of seasonal changes on the bacterial community structure of an activated sludge plant over a 3 4-week period. The protein profiles, over this study-period, indicated a re latively high (> 63%) similarity between the samples. The results indicated no specific protein pattern in the different zones or due to seasonal chan ges. This implicated that a stable bacterial community was present througho ut the study period.