Effect of nitrogen sources and vitamins on ligninolytic enzyme production by some white-rot fungi. Dye decolorization by selected culture filtrates

The effect of amino acids, complex nitrogen sources and vitamin addition on Trametes trogii, Trametes villosa and Coriolus versicolor var. antarcticus ligninolytic enzyme production, was evaluated. Dye decolorization by their culture filtrates was compared. Glutamic acid followed by peptone, were the best N sources for laccase and manganese peroxidase production. The three fungi produced two laccase isoenzymes (molecular weights from 38 up to 150 kDa); their pattern of production was not affected by medium composition. Although the response was not uniform, vitamin addition sometimes stimulated ligninolytic enzyme production, but never inhibited it. Thiamine induced manganese peroxidase production. T. trogii grown in glutamic acid produced culture filtrates with the highest laccase (188.3 U/ml) and manganese peroxidase activities (4.5 U/ml), rendering the best results in decolorization. These crude filtrates were able to decolorize in half hour (at pH 4.5, 30 °C): 13%, 23%, 40%, 46%, 82%, 94% and 95% of Gentian Violet, Xylidine, Congo Red, Malachite Green, Remazol Brilliant Blue R, Indigo Carmine and Anthraquinone Blue, respectively.