Laccase is a copper-containing polyphenol oxidase enzyme, which acts on a wide range of substrates. This enzyme is occur in many plant species and is widely distributed in fungi including wood-rotting fungi where it is often associated with lignin peroxidase, manganese dependent peroxidase, or both. Because of its importance in bioremediation, fungal cultures were screened for laccase production by plate testing method using the indicator compound guaiacol. The selected isolates of Aspergillus flavus were optimized for the production of Laccase grown on Glucose Asperagine agar medium. This exhibited the highest production on 5th day of incubation at pH= 5.5 and the optimum temperature for production was recorded at 30°C. The effect of metal ions on the activity of laccase production was also studied and observed that all the metal ions greatly inhibited the activity except Cu+2 and Ca+ ion. These two metal ions enhanced the activity of enzyme. Maximum inhibitory effect was observed in the presence of Zn+, Mn+2, and Cd+2 ions. To observe the effect of solvent systems on laccase production various solvent system were applied and found that, formic acid and acetaldehyde enhance the activity of enzyme but acetic acid showed maximum inhibitory effect. Whereas, β-mercaptoethanol and DTT did not affect the enzyme activity
