Screening and Characterization of Bacterial Laccase for Aromatic Compound Degradation

Abstract

The textile dyeing industry produces a large volume of waste water from the different steps in the dyeing process. The discharge from the dyeing industry constituting unfixed dyes, inorganic salts, heavy metal complexes etc., spoils the surrounding areas of industrial sites. There are 100 different Bacterial colonies were isolated and screened for Laccase-production using guaiacol drop assay. The isolated strain 5B and AM produced white on Nutrient agar. Upon gram staining the cells were found to be gram positive. The biochemical chacterization were done to identify the bacteria at genus level. Two bacterial laccase positive isolates were identified by molecular identification with 16S rDNA sequencing. The sequences obtained were analyzed using BLAST search to identify the corresponding Phylogenetic relatives. Based on the Identity score the Phylogenetic affiliations (Firmicutes) were confirmed. The whole cells were developed color change in both ABTS and SGZ within 5 minutes at pH 7.2.The Absorbance spectrum of ABTS and SGZ after oxidation by whole cell shows the characteristic laccase activity in the solution. The Sodium dodecyl sulphate polyacrylamide gel electrophoretic analysis of the partially purified laccase enzyme revealed the presence of different protein bands with molecular weights of 56.4 kDa respectively. The zymogram of the partially purified laccase enzyme revealed that the enzyme was in its active form which is seen as green color .The proposed work focused on the isolation and characterization of bacterial laccase from dye polluted environment.