Synthesis and characterization of surface-functionalized paramagnetic nanoparticles and their application to immobilization of α-acetolactate decarboxylase

Enzyme-inorganic nanoflowers/alginate microbeads: An enzyme immobilization system and its potential application

“…Activity evaluation ALDC can directly transform α-acetolactate into acetoin. The activities of free and immobilized ALDC were evaluated by calculating the rate of acetoin production under the standard conditions according to the method described elsewhere [2], with α-acetolactate as substrate. α-Acetolactate substrate was prepared by the following method: 5 μL of ethyl-2-acetoxy-2-methylacetoacetate, 40 μL of deionized water and 55 μL of NaOH solution (1 mol L −1 ) was mixed and incubated at 0°C for 15 min, following that 0.9 mL MES (pH 6.0) was added.…”

“…In the main fermentation of beer, diacetyl is a by-product formed from α-acetolactate, which could be further catalyzed to acetoin, but the residues of diacetyl in fermentation broth can lead to an unpleasant buttery taste in beer even with its concentration as low as 0.15 ppm [1,2]. The rate-limiting step of fermentation is the conversion of α-acetolactate into diacetyl, so the slow transformation lead to a long fermentation period of beer (2-12 weeks) [3,4].…”

“…[7][8][9][10][11] In recent years, nanobiocatalysis, in which enzymes are immobilized on/in nanostructured materials, has gathered growing attention due to its excellent performance in stabilizing/enhancing the enzymatic activity [12][13][14][15][16][17][18][19]. Hybrid protein-inorganic nanoflowers, first discovered by Zare's group, were synthesized through the co-precipitation of Cu 3 (PO 4 ) 2 and proteins in an aqueous buffer solution, in which the activity of enzyme was remarkably enhanced [12]. Subsequently, protein-inorganic nanoflowers were prepared by other group through co-precipitation Ca 2+ and enzyme [20,21].…”

Micro‐ and Nanocarriers for Immobilization of Enzymes

“…α-Acetolactate decarboxylase (α-ALDC) was covalently immobilized to paramagnetic Fe 3 O 4 -Si-NH 2 nanoparticles using 1'-carbonyldiimidazole (CDI). Such immobilized α-ALDC retained almost 65.35% of its initial activity and 31.05% of its initial activity after five times of reusing [111]. Another study reports of cholesterol oxidase (COX) immobilization to magnetic fluorescent core-shell structured nanoparticles, where immobilization consisted of silanization, linker molecule deposition, and enzyme coupling of GA and 3-aminopropyltriethoxysilane (APTES).…”

Studies on structure-function relationships of acetolactate decarboxylase from Enterobacter cloacae

“… 6,7 Immobilized ALDC has been applied in the traditional beer brewing process. 8 During fermentation, ALDC significantly increases the production rate and decreases the adverse flavour caused by diacetyl. 9 Apart from the catabolic degradation of α-acetolactate to acetoin, ALDC also participates in the biosynthesis of branched-chain amino acids.…”