resumo
The cultivation of Trametes versicolor for laccase production and cell growth were strongly dependent on experimental conditions namely physical and chemical parameters as well as nutrient availability and inducer stimulation. Biomass growth was compared for a rich medium and for a defined medium in two different temperatures. The best temperature was 28 degrees C and the maximum specific growth rates were mu(max) = 0.083 h(-1) for the rich medium and mu(max) = 0.043 h(-1) for the defined medium. It was clearly shown that laccase production is not associated with cell growth, indicating that this ligninolytic enzyme must be produced in the defined medium by a secondary metabolism. In order to obtain laccase induction, addition of solid lignin, lignosulphonates, veratryl alcohol, xylidine and ethanol was tested at different concentrations. To optimise laccase activity, the combined effect of inducer addition and simultaneously glucose suppression was studied. The best result for laccase induction (1240 U/L) was obtained with solid lignin, a by-product of pulp and paper industry and the higher laccase activity attained (1583 U/L) was obtained with the combined effect of xylidine addition and glucose suppression.
palavras-chave
WHITE-ROT FUNGI; KRAFT PULP; PHANEROCHAETE-CHRYSOSPORIUM; LIGNINOLYTIC FUNGI; DEGRADATION; DYES; 1-HYDROXYBENZOTRIAZOLE; BIODECOLORIZATION; PEROXIDASE; EFFLUENT
categoria
Biotechnology & Applied Microbiology
autores
Xavier, AMRB; Tavares, APM; Ferreira, R; Amado, F
nossos autores
Ana Maria Rebelo Barreto Xavier
Professor Auxiliar