Experimental investigation of the adsorption and desorption of cellulase enzymes on zeolite-β for enzyme recycling applications.

The recyclability of cellulase enzymes using zeolite and polyethylene glycol (PEG) was investigated. The cellulase enzymes from cellulose hydrolysate suspensions were adsorbed onto zeolite-β under typical working conditions (pH 5). PEG having a molecular weight of 200 Da and 20 kDa was used as an eluent to desorb the cellulase enzymes from zeolite-β. Adsorption and desorption profiles of cellulase enzymes were studied by varying pH, PEG concentration, and salt concentration. Maximum binding capacity, qm of the zeolite decreased by increasing the pH, or by introducing PEG. At pH 5, the qm of the zeolite was determined to be 121 × 10-3 g/g. About 24%, 51% and 75% of the adsorbed enzyme can be recovered using 1 M NaCl, PEG 200 and PEG 20000, respectively. The specific activity of the recovered enzyme increased by 57% due to the presence of residual PEG.