Characterization and catalytic property of surfactant-laccase complex in organic media

Citation
S. Okazaki et al., Characterization and catalytic property of surfactant-laccase complex in organic media, BIOTECH PR, 16(4), 2000, pp. 583-588
Citations number
30
Categorie Soggetti
Biotecnology & Applied Microbiology",Microbiology
Journal title
BIOTECHNOLOGY PROGRESS
ISSN journal
87567938 → ACNP
Volume
16
Issue
4
Year of publication
2000
Pages
583 - 588
Database
ISI
SICI code
8756-7938(200007/08)16:4<583:CACPOS>2.0.ZU;2-6
Abstract
The oxidation of o-phenylenediamine catalyzed in anhydrous organic solvents by surfactant-laccase complex was investigated. The complex was prepared b y utilizing a novel preparation technique in water-in-oil (W/O) emulsions. The surfactant-laccase complex effectively catalyzed the oxidation reaction in various dry organic solvents, while laccase, lyophilized from an aqueou s buffer solution in which its activity was optimized, exhibited no catalyt ic activity in nonaqueous media. To optimize the preparation and reaction c onditions for the surfactant-enzyme complexes, we examined the effects of p H in the water pool of W/O-emulsions, the concentration of enzyme and surfa ctant at the preparation stage, and the nature of organic solvents at the r eaction stage on the laccase activity in organic media. Surfactant-laccase complex showed a strong pH-dependent catalytic activity in organic media. I ts optimum activity was obtained when the complex was prepared at a pH of a bout 3. Interestingly, native laccase in an aqueous buffer solution exhibit ed an optimum activity at the same pH of 3. The optimum preparation conditi ons of surfactant-laccase complex were [laccase] = 0.8 mg/mL and [surfactan t] = 10 mM, and the complex showed the highest catalytic activity in toluen e among nine anhydrous organic solvents. The effect of a cosolubilized medi ator (1-hydroxybenzotriazole (HBT)) on the reaction was also investigated. The addition of HBT at the preparation stage of the enzyme complex did not accelerate the catalytic reaction because HBT was converted to an inactive benzotriazole (BT) by laccase. However, the addition of HBT at the reaction stage enhanced the catalytic performance by a factor of five compared to t hat without HBT.