Production of superparamagnetic nanobiocatalysts for green chemistry applications.
Immobilization of enzymes on solid supports is a convenient method for increasing enzymatic stability and enabling enzyme reuse. In the present work, a sorption-assisted surface conjugation method was developed and optimized to immobilize enzymes on the surface of superparamagnetic nanoparticles. An oxidative enzyme, i.e., laccase from Trametes versicolor was used as model enzyme. The immobilization method consists of the production of superparamagnetic nanoparticles by co-precipitation of FeCl2 and FeCl3. Subsequently, the particle surface is modified with an organosilane containing an amino group. Next, the enzymes are adsorbed on the particle surface before a cross-linking agent, i.e., glutaraldehyde is added which links the amino groups on the particle surface with the amino groups of the enzymes and leads to internal cross-linking of the enzymes as well. The method was optimized using response surface methodology regarding optimal enzyme and glutaraldehyde amounts, pH, and reaction times. Results allowed formulation of biocatalysts having high specific enzymatic activity and improved stability. The biocatalysts showed considerably higher stability compared with the dissolved enzymes over a pH range from 3 to 9 and in the presence of several chemical denaturants. To demonstrate the reusability of the immobilized enzymes, they were applied as catalysts for the production of a phenoxazinone dye. Virtually, 100 % of the precursor was transformed to the dye in each of the ten conducted reaction cycles while on average 84.5 % of the enzymatic activity present at the beginning of a reaction cycle was retained after each cycle highlighting the considerable potential of superparamagnetic biocatalysts for application in industrial processes.
Institute for Ecopreneurship, School of Life Sciences, University of Applied Sciences and Arts Northwestern Switzerland, Gründenstrasse 40, 4132, Muttenz, Switzerland. christoph.gasser@fhnw.ch.|Institute for Environmental Research, RWTH Aachen, Worringerweg 1, 52074, Aachen, Germany. christoph.gasser@fhnw.ch.
Christoph A
CA
Gasser
Institute for Ecopreneurship, School of Life Sciences, University of Applied Sciences and Arts Northwestern Switzerland, Gründenstrasse 40, 4132, Muttenz, Switzerland.
Erik M
EM
Ammann
Institute for Environmental Research, RWTH Aachen, Worringerweg 1, 52074, Aachen, Germany.|State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University Xianlin Campus, Xianlin Avenue 163, Nanjing, 210023, China.
Andreas
A
Schäffer
Institute for Chemistry and Bioanalytics, School of Life Sciences, University of Applied Sciences and Arts Northwestern Switzerland, Gründenstrasse 40, 4132, Muttenz, Switzerland.
Patrick
P
Shahgaldian
Institute for Ecopreneurship, School of Life Sciences, University of Applied Sciences and Arts Northwestern Switzerland, Gründenstrasse 40, 4132, Muttenz, Switzerland.|State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University Xianlin Campus, Xianlin Avenue 163, Nanjing, 210023, China.
Philippe F-X
PF
Corvini
D000327:Adsorption; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000378:metabolism*; D005976:Glutaral / Q000737:chemistry; D042845:Laccase / Q000378:metabolism*; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D010084:Oxidation-Reduction; D055454:Trametes / Q000201:enzymology*
D004800:Enzymes, Immobilized; D058185:Magnetite Nanoparticles; D042845:Laccase; D005976:Glutaral
Immobilization; Laccase; Magnetic biocatalysts; Magnetite nanoparticles; Phenoxazinone dye