The marc was separated from the extract by filtration, and the
filtered marc subjected to centrifugation at 7000 rpm for 20 min to
recover the remainder of the extract. The aqueous bio-flocculant
(AF) was kept at 4 C before further testing on its flocculating
property. A sample of AF was dried at 40 C until a constant weight
of the sample was obtained, then the dried bio-flocculant (DF) was
stored in a dessicator at room temperature prior to use. In order to
obtain the intrinsic extract yield, the dried sample of each experimental
run was further dried at 105 C for 24 h to obtain the dry
mass. The percentage of intrinsic extract yield was determined by
Equation (1):