For an efficient application of the soluble recombinant enzyme of rDyP,
immobilization of the enzyme was caried out to enhance and stabilize catalytic
efficiency of rDyP. Although several conventional immobilization methods have been
attempted for rDyP, no methods have been successful. Therefore, new catalysts
developed for exhaust gas removal were employed. They were silica-based
mesocellular foams and two silica-based porous materials, FSM-16 and AISBA-15,
which were chemically synthesized. Immobilization of rDyP on them was carried out
and immobilization efficiency was assessed. The overall efficiency was defined as
adsorption efficiency x activity efficiency to find the maximum efficiency. The
efficiency of rDyP immobilized on FSM-16 and AISBA-15 was maximum at pH 5 and
pH 4, respectively. FSM-16 showed advantages over AISBA-15 in terms of stronger
affinity for rDyP due to its anionic surface and much lower leaching of rDyP from
FSM-16. When the rDyP immobilized on FSM-16, an anthraquinone dye, RBBR, was
decolorized in repeated-batch mode, and eight sequential batches were possible, while
rDyP immobilized on AISBA-15 enabled only two batches.
For evaluation of the practical potential of rDyP, the turnover capacity of rDyP was
introduced. In order to minimize H2O2
inactivation for rDyP activity, four H2O2
supply
methods were attempted and the turnover capacity of each method was compared. The
continuous fed-batch supply of H2O2
and the stepwise fed-batch supply of the dye gave
the maximum turnover capacity of 20.4. At this turnover capacity, one liter of crude
rDyP solution containing 5,000 U could decolorize up to 102 g dye in 10h.
Keywords: AISBA-15, Adsorption, FSM-16, Immobilization, Inactivation by H2O2 , Leaching, Mesoporous materials, Overall efficiency, Remazol Brilliant Blue R, Recombinant DyP, rDyP, Turnover capacity.
