Metal-biochar composites are gaining increased attention for their potential to
improve enzyme immobilization efficiency and their environmentally friendly
nature. In this paper, the suitability of magnetite-biochar particles as a support for
the horseradish peroxidase (HRP) was investigated. The change in enzymatic
activity of the immobilized enzyme at different values of pH and temperature, as
well as stability over time, was measured. The enzyme was bound to the support
via glutaraldehyde as a crosslinker. The results showed that HRP can efficiently
bind to magnetite-biochar particles by covalent bonding. The immobilized enzyme
shows high activity at a wide range of pH and temperature. The highest activity of
the immobilized enzyme was recorded at pH 7 and at temperatures of 40°C. Also,
the immobilized enzyme retains 45% and 60% of its activity during storage at
temperatures of 25 and 10°C after a period of 30 days, respectively. After first
wash cycle, magnetite-biochar still retained 93% of HRP activity, however, further
washing significantly reduced enzyme activity.
