Reduced toxicity of malachite green decolorized by laccase produced from Ganoderma sp. rckk-02 under solid-state fermentation.
Statistical designs were applied for optimizing laccase production from a white-rot fungus, Ganoderma sp. rckk-02 under solid-state fermentation (SSF). Compared to unoptimized conditions [2,154 U/gds (Unit per gram of dry substrate)], the optimization process resulted in a 17.3-fold increase in laccase production (37,423 U/gds). The laccase produced was evaluated for its potential to decolorize a recalcitrant synthetic dye, malachite green. Laccase at dosage of 30 U/ml in presence of 1 mM of 1-hydroxybenzotriazole (HBT) almost completely decolorized 100 and 200 mg/l of malachite green in 16 and 20 h, respectively, at 30 °C, pH 5.5 and 150 rpm. While, higher dyes concentrations of 300, 400 and 500 mg/l were decolorized to 72, 62 and 55 % in 24, 28 and 32 h, respectively, under similar conditions. Furthermore, it was observed that the decolorized malachite green was less toxic towards the growth of five white-rot fungi tested viz. Crinipellis sp. RCK-1, Ganoderma sp. rckk-02, Coriolopsis Caperata RCK 2011, Phanerochaete chrysosporium K3 and Pycnoporous cinnabarinus PB. The present study demonstrates the potential of Ganoderma sp. rckk-02 to produce high titres of laccase under SSF, which can be exploited in conjunction with redox mediator for the decolorization of high concentrations of malachite green from water bodies.
Lignocellulose Biotechnology Laboratory, Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India.
Abha
A
Sharma
Lignocellulose Biotechnology Laboratory, Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India.
Bhuvnesh
B
Shrivastava
Lignocellulose Biotechnology Laboratory, Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India. kuhad85@gmail.com.
Ramesh Chander
RC
Kuhad
Decolorization; Detoxification; Ganoderma sp. rckk-02; Laccase; Malachite green