The chemical and mechanical differences between alginate-like exopolysaccharides isolated from aerobic flocculent sludge and aerobic granular sludge.
This study aimed to investigate differences in the gel matrix of aerobic granular sludge and normal aerobic flocculent sludge. From both types of sludge that fed with the same municipal sewage, the functional gel-forming exopolysaccharides, alginate-like exopolysaccharides, were isolated. These two exopolysaccharides were chemically fractionated, and investigated by FT-IR spectroscopy. The isolated polymers were made into a gel by calcium addition and the mechanical properties of these reconstituted gels were measured by a low load compression tester. The viscoelastic behavior of the gels was described by a generalized Maxwell model. The alginate-like exopolysaccharides derived from aerobic granules had significantly higher amount of poly(guluronic acid) blocks but lower amount of poly(guluronic acid-manuronic acid) blocks in the chemical structure, while the alginate-like exopolysaccharides derived from aerobic flocculent sludge had equal amount of poly(guluronic acid) blocks and poly(guluronic acid-manuronic acid) blocks. These differences result in a perfect gel-forming capability of alginate-like exopolysaccharides derived from aerobic granules and bestowed this exopolysaccharides gel a stronger mechanical property as compared to alginate-like exopolysaccharides derived from aerobic flocculent sludge. The different chemical and mechanical properties of these two exopolysaccharides contributed to the distinguished characteristics between aerobic granular sludge and aerobic flocculent sludge.
Department of Biotechnology, Delft University of Technology, Delft, The Netherlands. Yuemei.Lin@tudelft.nl
Y M
YM
Lin
P K
PK
Sharma
M C M
MC
van Loosdrecht
D000464:Alginates / Q000737:chemistry*; D002122:Calcium Chloride; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D011134:Polysaccharides / Q000737:chemistry*; D012722:Sewage / Q000737:chemistry*; D055682:Viscoelastic Substances; D014865:Waste Disposal, Fluid / Q000379:methods
D000464:Alginates; D006603:Hexuronic Acids; D011134:Polysaccharides; D012722:Sewage; D055682:Viscoelastic Substances; D020723:Glucuronic Acid; D002122:Calcium Chloride