17-42: Kinetics and recovery of cellulases immobilized on pH-responsive polymer brushes grafted to nanosilica and ferromagnetic particle

Monday, April 29, 2013
Exhibit Hall
Scott W. Pryor1, Ashani Samaratunga1, Olena Kudina2, Andriy Voronov2, Nurun Nahar1 and Sergiy Minko3, (1)Agricultural and Biosystems Engineering, NDSU, Fargo, ND, (2)Coatings and Polymeric Materials, NDSU, (3)Chemistry, Clarkson University
Recovery of cellulases has the potential to reduce net biomass saccharification costs through enzyme reuse in multiple hydrolysis cycles. We have attached cellulase (NS50013) and β-glucosidase (Novozyme 188) enzymes to polyacrylic acid (PAA) brushes grafted to nanosilica or ferromagnetic particles. Particles with the associated enzymes may be recovered from hydrolyzate via centrifugal or magnetic separation depending on the core particle material.  Fluorescent labeled enzymes are being used to determine the relative affinity of cellulases and β-glucosidase for the PAA brushes. Use of labeled enzymes has indicated that individual attached enzymes migrate slowly through and between individual grafted PAA brushes but do not detach into the bulk matrix. Hydrolysis, therefore, occurs while enzymes are closely associated with the PAA brushes. We have showed that the enzymes retain activity through multiple cycles of recovery and reuse. We are determining how enzyme density on the PAA brushes impacts the overall activity and required attached enzyme loading. We are also modeling the effect of temperature and pH on the activity and recoverability of immobilized enzymes.