Powderedenzymesweretransformedintotheirinsolublemagneticderivativesretainingtheircatalytic
activity.Enzymepowders(e.g.,trypsinandlipase)weresuspendedinvariousliquidmedianotallowing
their solubilization(e.g.,saturatedammoniumsulfateandhighlyconcentratedpolyethyleneglycolso-
lutions, ethanol,methanol,2-propanol)andsubsequentlycross-linkedwithglutaraldehyde.Magnetic
modification wassuccessfullyperformedatlowtemperatureinafreezer(20 °C) usingmagneticiron
oxidesnano-andmicroparticlespreparedbymicrowave-assistedsynthesisfromferroussulfate.Mag-
netized cross-linkedenzymepowderswerestableatleastfortwomonthsinwatersuspensionwithout
leakage of fixedmagneticparticles.Operationalstabilityofmagneticallyresponsiveenzymesduring
eight repeatedreactioncycleswasgenerallywithoutlossofenzymeactivity.Separationofmagnetically
modified cross-linkedpowderedenzymesfromreactionmixtureswassignificantly simplified dueto
their magneticproperties.