KRAFT PASTE BLEACHING WITH LIGNINOLITIC F UNGI

There have been proposed the biotechnological processes as an alternat ive to the chemical bleaching sequences of Kraft cellulose paste (Kraf t pulp), either for a reduction in the use of chemical compounds (preb leaching with hemicellulasas) or as a procedure able to carry out the bleaching in an ecological way (bleaching with ligninolitic fungi and their oxidative enzymes). The industrial application of the latter dep ends mostly on the deep knowledge of the bleaching mechanisms, where e xtracellular peroxidases and oxidases, produced by fungi and other env ironmetal factors are jointly implied, as for example, Mn2+ and organi c acids concentration, oxygen pressure, etc. With the aim to analyze e very factor about the biobleaching of Eucaliptus globulus Kraft paste, it was studied the effect of adding different organic acid concentrac ions (oxalic and glycolic acids) for different Mn+2 concentrations, th e influence of the oxygenation through air or oxygen and the effect of fungus morphology, as free or immobilized mycelium, on the enzymatic activity and the final whiteness of the paste.