Phenolic compounds as enhancers in enzymatic and electrochemical oxidation of veratryl alcohol and lignins.
Sixteen phenolic compounds, 14 of which naturally occurring, were compared to the synthetic 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) and violuric acid (VA) in terms of their ability to act as mediators/enhancers in: (1) laccase oxidation of veratryl alcohol as a lignin model compound, and (2) electrochemical oxidation of kraft and flax lignins. HPLC analysis revealed that the syringyl-type phenols methyl syringate and acetosyringone were the most efficient natural enhancers in the laccase oxidation of veratryl alcohol. Both compounds, though far from the performance of ABTS were able to generate veratraldehyde in amount similar to that obtained with VA. By contrast, the best performing phenolic enhancers for the electrochemical oxidation of lignins were sinapinaldehyde, vanillin, acetovanillone, and syringic acid. Catalytic efficiencies close to those achieved with ABTS and VA were calculated for these phenolic compounds.
Department of Chemical Engineering, Universitat Politècnica de Catalunya, Terrassa, Barcelona, Spain.
María
M
Díaz-González
Teresa
T
Vidal
Tzanko
T
Tzanov
D000098:Acetophenones / Q000378:metabolism; D052160:Benzothiazoles / Q000378:metabolism; D001592:Benzyl Alcohols / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D055664:Electrochemical Techniques; D005707:Gallic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D042845:Laccase / Q000378:metabolism; D008031:Lignin / Q000378:metabolism*; D010084:Oxidation-Reduction; D010636:Phenols / Q000378:metabolism*; D013451:Sulfonic Acids / Q000378:metabolism
D000098:Acetophenones; D052160:Benzothiazoles; D001592:Benzyl Alcohols; D010636:Phenols; D013451:Sulfonic Acids; C506133:methyl syringate; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; D005707:Gallic Acid; C051667:acetosyringone; D008031:Lignin; D042845:Laccase; C042197:veratryl alcohol