Je. Schmidt et Bk. Ahring, EXTRACELLULAR POLYMERS IN GRANULAR SLUDGE FROM DIFFERENT UPFLOW ANAEROBIC SLUDGE BLANKET (UASB) REACTORS, Applied microbiology and biotechnology, 42(2-3), 1994, pp. 457-462
Thermal extraction was used to quantify extracellular polymers (ECP) i
n granules from anaerobic upflow reactors. The optimal time for extrac
tion was determined as the time needed before the intracellular materi
al gives a significant contribution to the extracted extracellular mat
erial due to cell lysis. ECP contents of 41 to 92 mg.g(-1) volatile su
spended solids of granules were found depending on the type of granula
r sludge examined. The content of polysaccharides, protein and lipids
in the extracted ECP was quantified. Furthermore, the different methyl
esters of the lipids were determined and quantified. Lower amounts of
polysaccharides and proteins were found in the extracellular material
from granules grown on methanogenic and acetogenic substrates compare
d to granules grown on more complex substrates. In contrast, the lipid
content was lower on complex substrates. Changing the feed of an upfl
ow anaerobic sludge blanket reactor from a sugar-containing waste-wate
r to a synthetic waste-water containing acetate, propionate and butyra
te resulted in a decrease in both the protein and polysaccharide conte
nt and an increase in the lipid content of the extracellular material.
Furthermore, the amount of protein and polysaccharides in the ECP fou
nd under mesophilic conditions was significantly higher than under the
rmophilic conditions, while the lipid content was lower.