1. González K. 1, Arias E. 2, Carnicero A. 1, Perestelo F. 1 and Falcón M. A. 1 1. Department of Microbiology and Cellular Biology. University of La Laguna. Tenerife. Spain 2. Department of Microbiology and Parasitology. University of Alcalá. Alcalá de Henares. Spain “Improvements in an industrial lignin (Indulin AT) with laccase and laccase- mediator systems evaluated by spectroscopic and chromatographic techniques”

2. Laccase properties of Fusarium proliferatum Stability pHTemperature Optimal Temperature: 60ºC pH: 3.5 Kinetics properties

3. Characteristics of industrial lignin (Indulin AT) Klason lignin: 78% Reducing sugars: 0.12%

4. UV-Vis Spectrum of treated industrial lignin Outset of incubation with laccase Control Treated sample Coniferyl alcohol Isoeuglenol Acetovanillone QuinoneAbsorbance

5. Molecular mass distribution of industrial lignin 0 h ― 0 h control ― control Outset of incubation with laccase 7.6% Polymerization

6. Molecular mass distribution after 48 h 21 % Polimerization 48 h ― 48 h control ― control Min 30 UV-Vis spectra

7. Laccase-ABTS system Treated lignin ― Treated lignin control ― control Treated lignin ― Treated lignin control ― control Min 50.8 Min 66.1 Molecular mass distribution UV-Vis spectra 22% depolymerization

8. In summary: We can conclude that at the very beginning of the incubation the recovered Indulin AT showed an intense functionalization accompanied by a slight polymerization, which reached its maximum after 48 h of incubation. When ABTS was used as mediator a strong depolymerization and a new peak at 400 kDa were registered in the lignin elution profile. In addition, a strong oxidation was detected in the spectra below 50 min. Other mediators like HBT or violuric acid did not produce such changes. We can conclude that at the very beginning of the incubation the recovered Indulin AT showed an intense functionalization accompanied by a slight polymerization, which reached its maximum after 48 h of incubation. When ABTS was used as mediator a strong depolymerization and a new peak at 400 kDa were registered in the lignin elution profile. In addition, a strong oxidation was detected in the spectra below 50 min. Other mediators like HBT or violuric acid did not produce such changes.