Transformation of Halogen-, Alkyl-, and Alkoxy-Substituted Anilines by a Laccase of Trametes versicolor

Abstract

The laccase of the fungus Trametes versicolor was able to polymerize various halogen-, alkyl-, and alkoxy-substituted anilines, showing substrate specificity similar to that of horseradish peroxidase, whereas the laccase of Rhizoctonia praticola was active only with p-methoxyaniline. The substrate specificities of the enzymes were determined by using gas chromatography to measure the decrease in substrate concentration during incubation. With p-chloroaniline as the substrate, the peroxidase and the Trametes laccase showed maximum activity near pH 4.2. The transformation of this substrate gave rise to a number of oligomers, ranging from dimers to pentamers, as determined by mass spectrometry. The product profiles obtained by high-pressure liquid chromatography were similar for the two enzymes. A chemical reaction was observed between p-chloroaniline and an enzymatically formed dimer, resulting in the formation of a trimer. All three enzymes oxidized p-methoxyaniline to 2-amino-5-p-anisidinobenzoquinone dip -methoxyphenylimine, but only the T. versicolor laccase and the peroxidase caused the formation of a pentamer (2,5-dip -anisidinobenzoquinone dip -methoxyphenylimine). Our results demonstrate that in addition to horseradish peroxidase, a T. versicolor laccase can also polymerize aniline derivatives.

Phenolic Azo Dye Oxidation by Laccase from Pyricularia oryzae

“…Though hundreds of azo dyes are in industrial use, their environmental fate is not well understood. Laccases are copper-dependent enzymes produced by a number of fungi and plants, and they oxidize phenols and anilines in the presence of oxygen (1,2,8,21). In order to understand the role of laccases in azo dye degradation, the ability of laccase from P. oryzae to oxidize 4-(4Ј-sulfophenylazo)-phenol derivatives was examined.…”

“…Laccases, a class of copper-dependent phenol oxidases, are produced by plants and fungi (1,21). Laccases oxidize aromatic pollutants, such as anilines and phenols, in the presence of oxygen (1,2,8). In this reaction, the substrates are oxidized by one electron to generate the corresponding phenoxy radicals, which either polymerize to yield a phenolic polymer or are further oxidized by laccase to produce a quinone (1).…”

Antifungal Activity against Botrytis cinerea of 2,6-Dimethoxy-4-(phenylimino)cyclohexa-2,5-dienone Derivatives

“…Highest yields were obtained using 3-chloroaniline and 3,5-dichloroaniline as substrates ( 2b and 2h ) (Table 1). This high yield could be explained because the oxidation by laccase (from Trametes versicolor ) of 3-chloroaniline does not occur [33]. On the other hand, using methoxyanilines ( 2c and 2d ) low yields were obtained, due to a high amount of side products (data not shown).…”

Biodegradação de vinhaça proveniente do processo industrial de cana-de-açúcar por fungos

“…Entretanto, durante as últimas décadas tem sido demonstrado que lacase também pode oxidar unidades não-fenólicas de lignina na presença de certos compostos, conhecidos como mediadores, que incluem substratos artificiais (BOURBONNAIS; PAICE 1990, CALL; MÜCKE, 1997) e metabólitos fúngicos (EGGERT et al, 1996a). Lacases oxidam muitas substâncias recalcitrantes como: anilinas (HOFF et al, 1985), fluorene, pirene (SHÜITZENDÜEL; MAJANCHERCZK, 1999), estruturas relacionadas à lignina (BOYLE et al, 1992, BOURBONNAIS et al, 1996, compostos organofosforados (AMITAI et al, 1998), compostos modelos não-fenólicos de lignina (MAJCHERCZYK et al, 1999), fenóis (BOLLAG et al, 1988, d`ACUNZO et al, 2002, clorofenóis (BOLLAG et al, 2003), HPAs (MOUGIN et al, 2003), corantes aromáticos (SCHLIEPHAKE;LONERGAN, 1996;WESENBERG et al, 2003), e outras.…”