Abstract - Trametes versicolor growth and laccase induction with by-products of pulp and paper industry

Trametes versicolor growth and laccase induction with by-products of pulp and paper industry

Ana Maria Rebelo Barreto Xavier*
Departamento de Química
Universidade de Aveiro
Campos Universitário de Santiago
3810-193 Aveiro, Portugal
Tel: 351 234 370716
Fax: 351 234 370084
E-mail: abx@dq.ua.pt

Ana Paula Mora Tavares
Departamento de Química
Universidade de Aveiro
Campos Universitário de Santiago
3810-193 Aveiro, Portugal
Tel: 351 22 508 1686
Fax: 351 22 508 1674
E-mail: pdo05006@fe.up.pt

Rita Ferreira
Departamento de Química
Universidade de Aveiro
Campos Universitário de Santiago
3810-193 Aveiro, Portugal
E-mail: rmferreira@fade.up.pt

Francisco Amado
Departamento de Química
Universidade de Aveiro
Campos Universitário de Santiago
3810-193 Aveiro, Portugal
Tel: 351 23 437 0700
Fax 351 23 437 0084
E-mail: famado@dq.ua.pt

*Corresponding author

Financial support: The authors acknowledge the Instituto Nacional de Engenharia e Tecnologia Industrial (INETI) for Trametes versicolor cultures and and Fundação para Ciência e Tecnologia (FCT-Portugal), (POCTI/EQU/48489/2002). A.P.M. Tavares PhD grant (SFRH/DB/6606/2001).

Keywords: inducers, laccase, pulp and paper by-products, Trametes versicolor.

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 28ºC and the maximum specific growth rates were µ_max= 0.083 h^-1 for the rich medium and µ_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.