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

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 °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.

Pleurotus florida mediated biosynthesis of nanoparticles and biofortification.

The mycosynthesis of biogenic NPs using nanotechnology technique is an ecofriendly and economical approach. The extracellular mycelial extract of the Pleurotus florida fungi were used to biosynthesized Zn, Cu and Fe NPs using zinc sulphate, zinc chloride, copper sulphate, copper chloride ferrous sulphate and ferric chloride, precursor salts at 1.0 mM concentration. The color of reaction mixture was changed from (transparent to white, blue to green and yellow to brown) for Zn, Cu and Fe NPs during incubation period of 96 h at 25 ± 2 °C, indicating synthesis of NPs. Spectroscopy and microscopy techniques were used for the characterization of newly synthesized biogenic NPs. Whereas, the ICP-MS analysis revealed that copper chloride precursor salts produced high concentration of Cu biogenic NPs, followed by zinc chloride derived Zn NPs. The fortification with the biogenic NPs of Pleurotus florida mycelium exhibited high accumulation of the trace elements as compared to non-fortified mycelium. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-023-01307-z.

Comparative assessment on lignocellulose degrading enzymes and bioethanol production from spent mushroom substrate of Calocybe indica and Volvariella volvacea.

In the current study, we compared the production of extracellular lignocellulose degrading enzymes and bioethanol from the spent mushroom substrate (SMS) of Calocybe indica and Volvariella volvacea. From SMS at different stages of the mushroom development cycle, ligninolytic and hydrolytic enzymes were analysed. The activities of lignin-degrading enzymes, including lignin peroxidase (LiP), laccase, and manganese peroxidase (MnP) were maximal in the spawn run and primordial stages, while hydrolytic enzymes including xylanase, cellobiohydrolase (CBH), and carboxymethyl cellulase (CMCase) showed higher activity during fruiting bodies development and at the end of the mushroom growth cycle. SMS of V. volvacea showed relatively lower ligninase activity than the SMS of C. indica, but had the maximum activity of hydrolytic enzymes. The enzyme was precipitated with acetone and further purified with the DEAE cellulose column. The maximum yield of reducing sugars was obtained after hydrolysis of NaOH (0.5 M) pretreated SMS with a cocktail of partially purified enzymes (50% v/v). After enzymatic hydrolysis, the total reducing sugars were 18.68 ± 0.34 g/l (SMS of C. indica) and 20.02 ± 0.87 g/l (SMS of V. volvacea). We observed the highest fermentation efficiency and ethanol productivity (54.25%, 0.12 g/l h) obtained from SMS hydrolysate of V. volvacea after 48 h at 30 ± 2 °C, using co-culture of Saccharomyces cerevisiae MTCC 11,815 and Pachysolen tannophilus MTCC 1077.

Molecular characterization of shiitake medicinal mushroom, Lentinus edodes strains (higher Basidiomycetes) using RAPD and ITS sequencing.

The molecular phylogeny in seven strains of Lentinus edodes was studied based on RAPD and their internal transcribed spacers (ITS) regions. The strains were analyzed by RAPD with 20 arbitrary primers. Fifteen primers were found efficient for the amplification of the genomic DNA. The size of the polymorphic bands were in the range of 100-1000 bp. However, the size of ITS1-2 and ITS1-4 regions varied among the strains from 278 to 575 bp and from 410 to 616 bp, respectively. The higher alignment score of the ITS 1-2 region indicated more variability in the ITS 1-4 region. Thus, on the basis of RAPD-PCR and ITS sequencing it was found that strains LeC and LeI showed a high degree of divergence from all other strains.