Induction of a laccase Lcc9 from Coprinopsis cinerea by fungal coculture and its application on indigo dye decolorization

A fungal coculture system comprised of Coprinopsis cinerea Okayama 7 (#130) and Gongronella sp. w5 produced 900 times higher laccase activity than that in pure culture. A fungal laccase named Lcc9 was induced from C. cinerea for the first time by coculture. Lcc9 was purified, characterized, and found to have high activity toward phenolic substrates at the optimum pH of 6.5 and temperature of 60 °C. The laccase was stable at alkaline pH values, and its activity was not significantly affected by cations and organic solvents. Lcc9 showed decolorization capability toward indigo dye in the presence of 2,2′-azino-bis(3-ethylbenzothazoline-6-sulfonate), with 75% of indigo was decolorized by 50 U/L enzyme after 1 h of incubation under optimal catalytic conditions. These results showed that fungal coculture could active silent laccase gene, and the unusual properties make Lcc9 a candidate for specific industrial and environmental applications.