Selective oxidation and N-coupling by purified laccase of xylaria polymorpha MTCC-1100.

The chemical route of oxidation of methyl group to its aldehyde is inconvenient because once a methyl group is attacked, it is likely to be oxidized to the carboxylic acid and it is very difficult to stop the reaction at the aldehyde stage. Fungal laccases can be used for such oxidation reaction and the reaction can be completed sharply within 1-2 hrs. Coupling of amines are another important reactions known forfungal laccases; coupling reactions generally take 3-7 hrs. We have used the purified laccase of molecular weight 63 kDa obtained from the fungal strainXylaria polymorpha MTCC-100 with activity of 1.95 IU/mL for selective oxidation of 2-fluorotoluene, 4-fluorotoluene, and 2-chlorotoluene to 2-fluorobenzaldehyde, 4-fluorobenzaldehyde, and 2-chlorobenzaldehyde, respectively, and syntheses of 3-(3,4-dihydroxyphenyl)-propionic acid derivatives by N-coupling of amines. In each oxidation reactions, ABTS was used as mediator molecule. All the syntheses are ecofriendly and were performed at room temperature.