magnetite nanoparticles with covalently bound laccase was investigated by Kalkan
et al. (2012). Koyani and Vazquez-Duhalt (2016) tested chitosan nanoparticles with
encapsulated laccase in real bioremediation conditions. In soil, compost, and wastewater, the nano-encapsulated preparation showed higher stability against microbial
degradation and thus longer operational activity compared to the free enzyme.
Nanomembranes prepared from nanoparticles with immobilized enzymes represent a new hybrid nanocomposite and are attracting more and more attention.
Aghababaie et al. (2016) covalently immobilized a lipase enzyme on the surface
of Fe 3 O 4 @SiO 2 nanoparticles/ultrafiltration membrane, which greatly improved the
relative enzymatic activity and loading capacity in comparison to the unmodified
ultrafiltration membrane. Hou et al. (2014b) compared the immobilization of laccase
onto titanium nanoparticles and titanium-functionalized polyethersulfone membranes. These biocatalytic membranes showed greater immobilization efficiency,
displayed good enzyme stability along with higher tolerance to a wider range of pH
values and vigorous filtration conditions applied during the water treatment. Benefits
of both nanoparticles and membrane filtration system have been successfully combined. Membrane bioreactor with magnetic biocatalytic membrane was tested by
Gebreyohannes et al. (2015). The authors immobilized polygalacturonase and
xylanase and observed that the enzymes prevented membrane fouling, which may
be useful in industrial production, environmental remediation, or bio-energy
generation.
16.6.2 Novel Nanomaterials
Recently a growing interest in nanographene, nanotubes, nanofibers, nanogels, and
mesoporous nanospheres has been reported. Specific hybrid nanocomposites can be
synthetized by functionalization and combination of various nanostructures.
16.6.2.1 Nanographene
Graphene is made of a single layer of carbon atoms that are bonded together in a
repeating pattern of hexagons. Immobilization of enzymes onto graphene oxide
nanosheets can be performed via physical adsorption, covalent attachment, and
additional cross-linking; and show high thermal and solvent stability (Hermanová
et al. 2015). Graphene oxide nanosheets have been used for successful immobilization of chloroperoxidase (Ding et al. 2017). Laccase of Aspergillus oryzae was
immobilized on graphene nanosheets by Skoronski et al. (2017). The enzyme
quickly lost its activity after the second reaction cycle when immobilized via
physical adsorption, while the covalent binding technique retained around 80%
of the activity after 6 cycles. Self-assembled free-standing graphene oxide
352
M. Čvančarová et al.
et al. (2012). Koyani and Vazquez-Duhalt (2016) tested chitosan nanoparticles with
encapsulated laccase in real bioremediation conditions. In soil, compost, and wastewater, the nano-encapsulated preparation showed higher stability against microbial
degradation and thus longer operational activity compared to the free enzyme.
Nanomembranes prepared from nanoparticles with immobilized enzymes represent a new hybrid nanocomposite and are attracting more and more attention.
Aghababaie et al. (2016) covalently immobilized a lipase enzyme on the surface
of Fe 3 O 4 @SiO 2 nanoparticles/ultrafiltration membrane, which greatly improved the
relative enzymatic activity and loading capacity in comparison to the unmodified
ultrafiltration membrane. Hou et al. (2014b) compared the immobilization of laccase
onto titanium nanoparticles and titanium-functionalized polyethersulfone membranes. These biocatalytic membranes showed greater immobilization efficiency,
displayed good enzyme stability along with higher tolerance to a wider range of pH
values and vigorous filtration conditions applied during the water treatment. Benefits
of both nanoparticles and membrane filtration system have been successfully combined. Membrane bioreactor with magnetic biocatalytic membrane was tested by
Gebreyohannes et al. (2015). The authors immobilized polygalacturonase and
xylanase and observed that the enzymes prevented membrane fouling, which may
be useful in industrial production, environmental remediation, or bio-energy
generation.
16.6.2 Novel Nanomaterials
Recently a growing interest in nanographene, nanotubes, nanofibers, nanogels, and
mesoporous nanospheres has been reported. Specific hybrid nanocomposites can be
synthetized by functionalization and combination of various nanostructures.
16.6.2.1 Nanographene
Graphene is made of a single layer of carbon atoms that are bonded together in a
repeating pattern of hexagons. Immobilization of enzymes onto graphene oxide
nanosheets can be performed via physical adsorption, covalent attachment, and
additional cross-linking; and show high thermal and solvent stability (Hermanová
et al. 2015). Graphene oxide nanosheets have been used for successful immobilization of chloroperoxidase (Ding et al. 2017). Laccase of Aspergillus oryzae was
immobilized on graphene nanosheets by Skoronski et al. (2017). The enzyme
quickly lost its activity after the second reaction cycle when immobilized via
physical adsorption, while the covalent binding technique retained around 80%
of the activity after 6 cycles. Self-assembled free-standing graphene oxide
352
M. Čvančarová et al.