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Use of a Diffusion Model for Mono‐ and Bicomponent Anion‐Exchange of Two Isoenzymes of Glucoamylase from Aspergillus niger in a Fixed Bed
Author(s) -
Soriano Roberto,
Bautista L. Fernando,
Martínez Mercedes,
Aracil José
Publication year - 2008
Publication title -
biotechnology progress
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 129
eISSN - 1520-6033
pISSN - 8756-7938
DOI - 10.1021/bp0340133
Subject(s) - aspergillus niger , isozyme , diffusion , chemistry , aspergillus , biochemistry , ion , microbiology and biotechnology , enzyme , biology , organic chemistry , thermodynamics , physics
The adsorption of glucoamylases I and II (GA I and GA II, respectively) from Aspergillus niger on the anion exchanger DEAE‐Toyopearl 650 was studied in fixed‐bed experiments, and the effect of temperature, flowrate, inlet concentration, bed length, and particle size on the process was characterized. The anion exchanger showed a higher adsorption capacity for the more active isoenzyme GA I in all experimental conditions studied. A mathematical model accounting for external and pore diffusion and nonlinear equilibrium isotherm (for GA I) was used to fit the experimental breakthrough curves, showing very accurate fittings in all of the operating conditions. The values of the pore diffusion coefficient at 15, 20, and 25 °C were, respectively, 1.25 × 10 ‐ 11 , 1.46 × 10 ‐ 11 and 1.83 × 10 ‐ 11 (for GA I) and 1.82 × 10 ‐ 11 , 2.44 × 10 ‐ 11 and 2.73 × 10 ‐ 11 (for GA II) m 2 /s. Bicomponent adsorption experiments showed no significant interference effects between GA I and GA II, and so the mathematical model was again used to fit these experiments, yielding very satisfactory results.