Magnetically modified spent grain as a low-cost, biocompatible and smart carrier for enzyme immobilisation

Background Food and feed technology and biotechnology benefit from the use of immobilised enzymes. New low-cost enzyme carriers exhibiting high biocompatibility and response to external magnetic field can substantially improve the application potential of immobilised enzyme systems. Results Ferrofluid-modified spent grain was used as a low-cost, biocompatible and magnetically responsive carrier for the immobilisation of Candida rugosa lipase. Several immobilisation procedures were tested using both native and poly(ethyleneimine)-modified magnetic spent grain. Activity of immobilised lipase per unit mass of carrier, operational stability, time stability and Michaelis constant were compared. In general, magnetic spent grain modified with poly(ethyleneimine) bound a smaller amount of active lipase than unmodified magnetic spent grain, but the operational and storage stabilities of enzyme immobilised on poly(ethyleneimine)-modified carrier were very high. Conclusion Ferrofluid-modified spent grain can be a promising low-cost magnetic carrier for enzyme immobilisation, applicable e.g. in food and feed technology and biotechnology.(c) 2012 Society of Chemical Industry