Reversible immobilization of glucoamylase by ionic adsorption on sepabeads coated with polyethyleneimine.
Glucoamylase (GA) from Aspergillus niger was immobilized via ionic adsorption onto DEAE-agarose, Q1A-Sepabeads, and Sepabeads EC-EP3 supports coated with polyethyleneimine (PEI). After optimization of the immobilization conditions (pH, polymer size), it was observed that the adsorption strength was much higher in PEI-Sepabeads than in Q1A-Sepabeads or DEAE-supports, requiring very high ionic strength to remove glucoamylase from the PEI-supports (e.g., 1 M NaCl at pH 5.5). Thermal stability and optimal temperature was marginally improved by this immobilization. Recovered activity depended on the substrate used, maltose or starch, except when very low loading was used. The optimization of the loading allowed the preparation of derivatives with 750 IU/g in the hydrolysis of starch, preserving a high percentage of immobilized activity (around 50%).
Departamento de Biocatálisis, Instituto de Catálisis, CSIC, Campus Universidad Autónoma, Cantoblanco, 28049 Madrid, Spain.
Rodrigo
R
Torres
Benevides C C
BC
Pessela
Cesar
C
Mateo
Claudia
C
Ortiz
Manuel
M
Fuentes
Jose M
JM
Guisan
Roberto
R
Fernandez-Lafuente
D000327:Adsorption; D001234:Aspergillus niger / Q000201:enzymology; D002411:Cation Exchange Resins; D004800:Enzymes, Immobilized / Q000037:antagonists & inhibitors / Q000378:metabolism*; D005087:Glucan 1,4-alpha-Glucosidase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D007477:Ions; D011094:Polyethyleneimine / Q000737:chemistry*
D002411:Cation Exchange Resins; D004800:Enzymes, Immobilized; D007477:Ions; D011094:Polyethyleneimine; D005087:Glucan 1,4-alpha-Glucosidase