New and strong ionic exchange resins have been prepared by the simp
le and rapidionic adsorption of anionic po
lymers (su
lfate-dextran) on porous supports activatedwith the opposite ionic group (DEAE/MANAE). Ionic exchange properties of suchcomposites were strong
ly dependent on the size of the ionic po
lymers as we
ll as onthe conditions of the ionic coating of the so
lids with the ionic po
lymers (optima
lconditions were 400 mg of su
lfate-dextran 5000 kDa per gram of support). Around80% of the proteins contained in crude extracts from
Escherichia coli and
Acetobacterturbidans cou
ld be adsorbed on these porous composites even at pH 7. This interactionwas stronger than that using conventiona
l carboxymethy
l ce
llu
lose (CMC) and evenothers such as supports coated with aspartic-dextran po
lymer. By means of thesequentia
l use of the new supports and supports coated with po
lyethy
leneimine (PEI),a
ll proteins from crude extracts cou
ld be immobi
lized. In fact, a
large percentage (over50%) cou
ld be immobi
lized on both supports. Fina
lly, some industria
lly re
levantenzymes (
le">-ga
lactosidases from
Aspergillus oryzae,
Kluyveromyces lactis, and
Thermussp. strain T2,
lipases from
Candida antarctica A and
B, Candida rugosa,
Rhizomucormiehei, and
Rhyzopus oryzae and bovine pancreas trypsin and chymotrypsin) havebeen immobi
lized on these supports with very high activity recoveries and immobi
lization rates. After enzyme inactivation, the protein cou
ld be fu
lly desorbed from thesupport, and then the support cou
ld be reused for severa
l cyc
les. Moreover, in someinstances the enzyme stabi
lity was significant
ly improved, main
ly in the presence oforganic so
lvents, perhaps as a consequence of the high
ly hydrophi
lic microenvironmentof the support.