An Easy Method for Screening and Detection of Laccase Activity

An instrument-free assay was developed for simultaneous detection of laccase activity in a large number of samples as diverse as screening of laccase-producing microbial cultures or chromatographic fractions.

Dried paper discs previously impregnated with 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) were placed on a flat-bottom microplate (a simple way to avoid misidentification) and loaded with an aliquot from each sample.

Discs corresponding to samples containing laccase activity become green-bluish colored within first ten minutes of reaction, allowing direct detection through simple naked-eye inspection.

As an example, this easy process was applied to the laccase purification in order to eliminate chromatographic fractions that did not contain laccase activity, thus reducing the number of spectrophotometric assays.