Modeling the Effect of pH and Temperature for Cellulases Immobilized on Enzymogel Nanoparticles.
Production costs of cellulosic biofuels can be lowered if cellulases are recovered and reused using particulate carriers that can be extracted after biomass hydrolysis. Such enzyme recovery was recently demonstrated using enzymogel nanoparticles with grafted polymer brushes loaded with cellulases. In this work, cellulase (NS50013) and β-glucosidase (Novozyme 188) were immobilized on enzymogels made of poly(acrylic acid) polymer brushes grafted to the surface of silica nanoparticles. Response surface methodology was used to model effects of pH and temperature on hydrolysis and recovery of free and attached enzymes. Hydrolysis yields using both enzymogels and free cellulase and β-glucosidase were highest at the maximum temperature tested, 50 °C. The optimal pH for cellulase enzymogels and free enzyme was 5.0 and 4.4, respectively, while both free β-glucosidase and enzymogels had an optimal pH near 4.4. Highest hydrolysis sugar concentrations with cellulase and β-glucosidase enzymogels were 69 and 53 % of those with free enzymes, respectively. Enzyme recovery using enzymogels decreased with increasing pH, but cellulase recovery remained greater than 88 % throughout the operating range of pH values less than 5.0 and was greater than 95 % at pH values below 4.3. Recovery of β-glucosidase enzymogels was not affected by temperature and had little impact on cellulase recovery.
Department of Agricultural and Biosystems Engineering, North Dakota State University, Fargo, ND, 58108-6050, USA.
Ashani
A
Samaratunga
Olena
O
Kudina
Nurun
N
Nahar
Andrey
A
Zakharchenko
Sergiy
S
Minko
Andriy
A
Voronov
Scott W
SW
Pryor
D000180:Acrylic Resins / Q000737:chemistry; D056804:Biofuels; D018533:Biomass; D002480:Cellulase / Q000737:chemistry*; D002482:Cellulose / Q000737:chemistry*; D004800:Enzymes, Immobilized / Q000737:chemistry*; D017743:Equipment Reuse; D005163:Factor Analysis, Statistical; D005782:Gels; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D053758:Nanoparticles / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry; D013696:Temperature; D001617:beta-Glucosidase / Q000737:chemistry*
D000180:Acrylic Resins; D056804:Biofuels; D004800:Enzymes, Immobilized; D005782:Gels; C006903:carbopol 940; D012822:Silicon Dioxide; D002482:Cellulose; D001617:beta-Glucosidase; D002480:Cellulase