Synthesis of Aldehydes by Layer‐by‐Layer Immobilized Laccases in the Presence of Redox Mediators

Abstract

Laccase from Trametes versicolor was immobilized on Eupergit®C250L and alumina particles. The immobilized enzyme was protected by coating with oppositely charged polyelectrolytes by means of the Layer‐by‐Layer (LbL) technique. Enzymatic assay showed that immobilized laccase was more stable than free enzyme at different pH and temperatures without loss of catalytic efficiency. Immobilized laccase based catalysts were efficiently used for the selective oxidation of alcohols to aldehydes in the presence of redox mediators such as ABTS (2,2′‐azinobis‐(3‐ethylbenzothiazoline‐6‐sulphonic acid), HBT (1‐hydroxybenzotriazole), VLA (violuric acid) and TEMPO (2,2,6,6‐tetramethyl‐1‐piperidinyloxy free radical)

Laccase Immobilized Fe3O4-Graphene Oxide Nanobiocatalyst Improves Stability and Immobilization Efficiency in the Green Preparation of Sulfa Drugs

“…The activities of free and immobilized laccase were measured using ABTS as a standard in Na-acetate buffer (0.1 M, pH = 5.0) as described previously [52].…”

Preparation and characterization of laccases immobilized on magnetic nanoparticles and their application as a recyclable nanobiocatalyst for the aerobic oxidation of alcohols in the presence of TEMPO

“…The formation of carboxylic acids from p-chloro and m-chloro benzyl alcohols is probably due to stereoelectronic effects exerted by the chlorine substituent on the oxoammonium ion intermediate. 33 Cinnamyl alcohol as a model for allylic alcohol can be transformed into the corresponding aldehyde under the same reaction as well (Table 5, entry 8).…”

Laccase-Mediated Enhancement of the Antioxidant Activity of Propolis and Poplar Bud Exudates

“… 26 , 27 The reactivity of laccases ( E 0 = 0.5–0.8 V vs normal hydrogen electrode) 28 toward high-redox-potential substrates can be increased in the presence of redox mediators in the so-called laccase-mediator systems (LMSs). 29 Redox mediators, such as 2,2,6,6-tetramethyl-1-piperidinyloxy free radical (TEMPO; E 0 = 0.75 V), 30 diffuse far away from the active site of the enzyme in the bulk of the solution, increasing the possible biotechnological applications. 31 TEMPO undergoes a one-electron transfer mechanism to form the oxoammonium ion intermediate.…”

“…They are tolerant to non-natural media (organic solvents and ionic liquids) and resistant to different types of inhibitors . Examples of the applications of nonaqueous enzymology in the oxidation of polyphenols with laccases have already been reported. , The reactivity of laccases ( E 0 = 0.5–0.8 V vs normal hydrogen electrode) toward high-redox-potential substrates can be increased in the presence of redox mediators in the so-called laccase-mediator systems (LMSs) . Redox mediators, such as 2,2,6,6-tetramethyl-1-piperidinyloxy free radical (TEMPO; E 0 = 0.75 V), diffuse far away from the active site of the enzyme in the bulk of the solution, increasing the possible biotechnological applications .…”