title: Extraction of activated sludge bacteria exopolymers by ultrasonication.
abstract: Ultrasonication for the extraction of activated sludge exopolymers was evaluated by total cell count, exopolymer extraction and transmission electron microscopy (TEM). A high deflocculation was achieved after 30 s of sonication in PBS (phosphate-buffered saline). TEM showed that cell lysis was minimal only when sludges were sonicated for 30 s. For sludges sonicated for 30, 90 and 420 s and stained with Ruthenium Red, exopolymers were not extracted on a large scale without considerable cell lysis. Sludges sonicated for 30 s in EDTA gave a larger fraction of damaged cells and also showed copious amounts of attached exopolymers.
mesh_terms: D001420:Bacteria, Aerobic / Q000254:growth & development / Q000378:metabolism* / Q000528:radiation effects* / Q000648:ultrastructure; D018441:Biofilms / Q000254:growth & development* / Q000528:radiation effects*; D019149:Bioreactors / Q000382:microbiology; D002449:Cell Aggregation / Q000528:radiation effects; D018929:Cell Culture Techniques / Q000379:methods; D002455:Cell Division / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis* / Q000302:isolation & purification*; D012722:Sewage / Q000382:microbiology*; D013010:Sonication
chemical_list: D011135:Polysaccharides, Bacterial; D012722:Sewage