title: Immobilization of L-arabinitol dehydrogenase on aldehyde-functionalized silicon oxide nanoparticles for L-xylulose production.
abstract: L-Xylulose is a potential starting material for therapeutics. However, its translation into clinical practice has been hampered by its inherently low bioavailability. In addition, the high cost associated with the production of L-xylulose is a major factor hindering its rapid deployment beyond the laboratory. In the current study, L-arabinitol 4-dehydrogenase from Hypocrea jecorina (HjLAD), which catalyzes the conversion of L-arabinitol into L-xylulose, was immobilized onto various carriers, and the immobilized enzymes were characterized. HjLAD covalently immobilized onto silicon oxide nanoparticles showed the highest immobilization efficiency (94.7 %). This report presents a comparative characterization of free and immobilized HjLAD, including its thermostability and kinetic parameters. The thermostability of HjLAD immobilized on silicon oxide nanoparticles was more than 14.2-fold higher than free HjLAD; the t1/2 of HjLAD at 25 °C was enhanced from 190 min (free) to 45 h (immobilized). In addition, the immobilized HjLAD retained 94 % of its initial activity after 10 cycles. When the immobilized HjLAD was used to catalyze the biotransformation of L-arabinitol to L-xylulose, 66 % conversion and a productivity of 7.9 g · h(-1) · L(-1) were achieved. The enhanced thermostability and reusability of HjLAD suggest that immobilization of HjLAD onto silicon oxide nanoparticles has the potential for use in the industrial production of rare sugars.
authors.affiliation: Department of Chemical Engineering, Konkuk University, 1 Hwayang-Dong, Gwangjin-Gu, Seoul, 143-701, Korea.
authors.forename: Raushan Kumar
authors.initials: RK
authors.lastname: Singh
authors.forename: Manish Kumar
authors.initials: MK
authors.lastname: Tiwari
authors.forename: Ranjitha
authors.initials: R
authors.lastname: Singh
authors.forename: Jung-Rim
authors.initials: JR
authors.lastname: Haw
authors.forename: Jung-Kul
authors.initials: JK
authors.lastname: Lee
mesh_terms: D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D053758:Nanoparticles / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D013401:Sugar Alcohol Dehydrogenases / Q000737:chemistry / Q000378:metabolism*; D013696:Temperature; D014242:Trichoderma / Q000201:enzymology; D014996:Xylulose / Q000378:metabolism*
chemical_list: D004800:Enzymes, Immobilized; D014996:Xylulose; D012822:Silicon Dioxide; D013401:Sugar Alcohol Dehydrogenases; C440029:L-arabinitol 4-dehydrogenase