Abstract

In our search for a laccase producer from unconventional sources, the marine derived fungus Alternaria tenuissima KM651985 was isolated from decayed wood. It was identified on the basis of morphological and molecular taxonomy and got the Genbank accession number KM651985. Two statistical experimental designs were employed to enhance laccase production. At first, a two level Plackett–Burman design was employed to screen the medium constituents and inducers that significantly affect the enzyme production. Second experiment was important for optimization of the most effective constituents and inducers using central composite design. Applying the above methods revealed that guaiacol (2 mM), copper sulphate (3 mM) and wheat bran (46.82 g/l) were the most effective factors affecting laccase production. A maximal enzyme activity of 91.84 U/ml was more than 6.33-folds the activity obtained using the basal medium. Application of A. tenuissima KM651985 culture medium containing laccase to decolorize two structurally different synthetic dyes was done successfully. This is the first report on the statistical optimization of the marine-derived A. tenuissima KM651985 laccase enzyme and its applications for dyes decolorization.

Key words: Alternaria tenuissima KM651985, Response Surface Methodology, Plackett–Burman Design, optimization, decolorization.