Application of ligninolytic potentials of a white-rot fungus Ganoderma lucidum for degradation of lindane

摘要

Lindane, a broad-spectrum organochlorine pesticide, has caused a widespread environmental contamination along with other pesticides due to wrong agricultural practices. The high efficiency, sustainability and eco-friendly nature of the bioremediation process provide an edge over traditional physico-chemical remediation for managing pesticide pollution. In the present study, lindane degradation was studied by using a white-rot fungus, Ganoderma lucidum GL-2 strain, grown on rice bran substrate for ligninolytic enzyme induction at 30 degrees C and pH 5.6 after incorporation of 4 and 40 ppm lindane in liquid as well as solid-state fermentation. The estimation of lindane residue was carried out by gas chromatography coupled to mass spectrometry ( GC-MS) in the selected ion monitoring mode. In liquid-state fermentation, 100.13 U/ml laccase, 50.96 U/ml manganese peroxidase and 17.43 U/ml lignin peroxidase enzymes were obtained with a maximum of 75.50 % lindane degradation on the 28th day of incubation period, whereas under the solid-state fermentation system, 156.82 U/g laccase, 80.11 U/g manganese peroxidase and 18.61 U/g lignin peroxidase enzyme activities with 37.50% lindane degradation were obtained. The lindane incorporation was inhibitory to the production of ligninolytic enzymes and its own degradation but was stimulatory for extracellular protein production. The dialysed crude enzyme extracts of ligninolytic enzymes were though efficient in lindane degradation during in vitro studies, but their efficiencies tend to decrease with an increase in the incubation period. Hence, lindane-degrading capabilities of G. lucidum GL-2 strain make it a potential candidate for managing lindane bioremediation at contaminated sites.