Universidade do Minho. Departamento de Engenharia Biológica (DEB)
Abstract
Aiming at the production of enzymes using solid wastes from the tobacco industry, the solid fermentation
kinetics of Aspergillus niger and Aspergillus terreus using waste of dark tobacco and Virginia tobacco as
substrate were characterized.
The efficiency of the fermentation process was evaluated by determining the enzymatic activity of the three
enzymes that constitute the cellulose enzymatic system (CMCase, PFase and Xylanase).
The results obtained led to the establishment of the best initial conditions of fermentation and the selection
of the most efficient microorganism for enzyme production. The best results were obtained with
Aspergillus terreus for both tobacco residues. In the case of black tobacco, the best incubation temperature
was 31 ºC for the enzymes CMCase and Xylanase and 36 ºC for the PFase and initial pH 5.5 for the three
enzymes. For the Virginia tobacco, the best incubation temperature and initial pH are the same for the three
enzymes, 36 ºC and 5.5 respectively.
The biological activity of the fermented tobacco residues was evaluated being the highest rate of inhibition
of microbial growth – 72% - obtained with the residue of Virginia tobacco treated with Aspergillus niger