Ionic liquids as alternative co-solvents for laccase: Study of enzyme activity and stability

• Published in: Biotechnology and bioengineering Vol. 101; no. 1; pp. 201 - 207
• Main Authors: Tavares, Ana Paula Mora, Rodriguez, Oscar, Macedo, Eugénia A
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.09.2008; Wiley; Wiley Subscription Services, Inc
• Subjects: Biochemistry; Biological and medical sciences; Biotechnology; Chemical bonds; Computer Simulation; Enzyme Activation; Enzyme Stability; Enzymes; Fundamental and applied biological sciences. Psychology; ionic liquids; Ionic Liquids - chemistry; kinetic parameters; Kinetics; laccase; Laccase - chemistry; Liquids; Models, Chemical; organic solvents; Solvents; Solvents - chemistry; stability; kinetic parameters; Organic solvent; organic solvents; Stability; Enzymatic activity; Enzyme; Oxidoreductases; Kinetic parameter; ionic liquids; Laccase; Ionic liquid
• ISSN: 0006-3592; 1097-0290
• DOI: 10.1002/bit.21866

The activity and stability of commercial laccase (DeniLite base) in three different water soluble ionic liquids (ILs) (1-ethyl-3-methylimidazolium 2-(2-methoxyethoxy) ethylsulfate, [emim][MDEGSO₄], 1-ethyl-3-methylimidazolium ethylsulfate, [emim][EtSO₄], and 1-ethyl-3-methylimidazolium methanesulfonate, [emim][MeSO₃]) have been studied and compared to that in two organic solvents (acetonitrile and dimethyl sulfoxide). Initial enzyme activities were similar among the ILs if the same conditions were used. A high reduction on initial enzyme activity was found with acidic pH (5.0). The effect of pH and solvent concentration on enzyme stability were investigated in more detail for 1 week. The enzyme maintained a high stability at pH 9.0 for all ILs tested. [emim][MDEGSO₄] was the most promising IL for laccase with an activity loss of about 10% after 7 days of incubation. The kinetic studies in the presence of ABTS as substrate allowed to calculate the Michaelis- Menten parameters. Good agreement was found between experimental data and calculated values using the Michaelis-Menten mechanism, with a total average relative deviation of 2.1%. Biotechnol. Biotechnol. Bioeng. 2008;101: 201-207.