Screening of Trametes strains for efficient decolorization of malachite green at high temperatures and ionic concentrations

• Screening of 18 Trametes strains for MG decolorization.
• Trametes trogii Berk S0301 was chose as a potential strain for MG decolorization.
• Cu2+ and Tween 80 obviously enhanced laccase production by strain S0301.
• S0301 laccase showed efficient decolorization for all dyes tested at 60 °C.
• MG decolorization by S0301 laccase was resistant to Mn2+, Co2+ and Na+.

Trametes (synonym Coriolous) species are the most important sources for laccases with attractive properties. Several Trametes species were screened for their ability to produce laccase and decolorize malachite green (MG). Trametes trogii Berk S0301 was chosen for further study because it showed the highest 2,2′-azino bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) oxidization ability, which is closely correlated with MG decolorization. The laccase activity of T. trogii Berk S0301 was enhanced up to 34.3-fold and 5.6-fold by Cu2+ (1.5 mM) and Tween 80 (7 g L−1), respectively. Mn2+, Mg2+, Zn2+, Co2+ and Na+ (100 mM) only slightly (less than 10% inhibition) affected MG decolorization by the crude laccase of T. trogii Berk S0301. MG was decolorized effectively at pH 4.5–7.0 and 30–80 °C with an optimum decolorization at pH 6 and 50–70 °C. Phyto- and micro-toxicity tests revealed that less toxic metabolites were formed after laccase treatment. The present work demonstrates that strain T. trogii Berk S0301 and its laccase may facilitate novel and more efficient bio-catalytic process applications.