Immobilization of pullulanase from Bacillus licheniformis on magnetic multi-walled carbon nanotubes for maltooligosaccharide productionNazli Ece Varan, Dilek Alagöz, Ali Toprak, Hatice Korkmaz Güvenmez, and Deniz Yildirim Sciences & Letters Faculty, Chemistry Department, Cukurova University, Adana, Turkey
E-mail: evaran@cu.edu.tr Received: 6 August 2024 Accepted: 23 October 2024 Abstract: In this study, Fe3O4-coated multi-walled carbon nanotubes (MWCNT-Fe3O4) or nickel oxide-coated multi-walled carbon nanotubes (MWCNT-NiO) were activated with 3-Glycidyloxypropyl)trimethoxysilane (3-GPTMS) to create oxirane groups. Pullulanase from Bacillus licheniformis was covalently immobilized on these magnetic MWCNTs to obtain magnetically separable immobilized pullulanase preparations (MWCNT-Fe3O4@Pul or MWCNT-NiO@Pul) for producing maltooligosaccharides (MOSs) from pullulan. The highest recovered activity values were 78% and 85% respectively, for MWCNT-Fe3O4@Pul and MWCNT-NiO@Pul after 24 h of immobilization at pH 7.0. The optimal pH and temperature were found to be 5.5 and 45 °C for free pullulanase, whereas the corresponding values were 5.5 and 50 °C for both immobilized pullulanase preparations. The thermal stabilities of MWCNT-Fe3O4@Pul and MWCNT-NiO@Pul increased by 6.2- and 8.2-fold, respectively, at 50 °C. The catalytic efficiencies of MWCNT-Fe3O4@Pul and MWCNT-NiO@Pul were calculated to be 0.8- and 1.1-fold that of free pullulanase, respectively. After 24 h of hydrolysis, MOS yields were determined to be 470 and 490 mg MOS/g pullulan for MWCNT-Fe3O4@Pul and MWCNT-NiO@Pul, respectively. The remaining activities were 86% and 85% for MWCNT-Fe3O4@Pul and MWCNT-NiO@Pul after 10 reuses, respectively. Keywords: Pullulanase; Immobilization; Magnetic multi-walled carbon nanotubes; Maltooligosaccharide Full paper is available at www.springerlink.com. DOI: 10.1007/s11696-024-03764-0
Chemical Papers 78 (18) 9529–9542 (2024) |
Thursday, December 26, 2024 
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