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- Title
Immobilization of CGTases from Bacillus Circulans and Bacillus Pseudalcaliphilus on Aminosilane and PEI Modified Magnetic Nanoparticles and Modified Silica Particles.
- Authors
Ivanova, V.; Tonkova, A.; Atanassova, N.; Safarikova, M.; Hristov, J.
- Abstract
The extracellular enzymes cyclodextrin glucanotransferases produced by Bacillus circulans ATCC 21783, Bacillus pseudalcaliphilus strain 8SB and Bacillus pseudalcaliphilus strain 20RF were immobilized by covalent linking via glutaraldehyde to silanized magnetic nanoparticles treated with PEI, silanized magnetite and magnetic nanoparticles, and commercially functionalized silica nano- and microparticles in order to study the immobilization capacities of the carriers, the activity recovery and some biochemical characteristics of the enzymes after immobilization. The immobilized enzymes showed a high operational stability after twelve re-uses. The temperature optima of CGTases from alcaliphilic strains of B. pseudalcaliphilus were shifted from 60°C to 65°C after immobilization on the silica particles and magnetic nanosupports. The pH activity profiles of immobilized CGTases from Bacillus pseudalcaliphilus strains were affected by the immobilization. Both enzymes showed two pHoptima - at pH 6.0 and pH 9.0. Their maximal activities were at pH 9.0 whereas the maximal activities of the native enzymes are at pH 6.0. No significant increase of pH stability profiles was observed, whereas the thermal stabilities of immobilized GTases were superior to that of free CGTases when immobilized on aminosilane and PEI modified magnetic nanoparticles.
- Subjects
NANOPARTICLES; BACILLUS circulans; THERMAL stability; GLUTARALDEHYDE; IMMOBILIZATION stress
- Publication
International Review of Chemical Engineering - Rapid Communications, 2010, Vol 2, Issue 2, p278
- ISSN
2035-1755
- Publication type
Article