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Author: search.filters.author.Mohan Balakrishnan, R.M.Subject: search.filters.subject.Biosorption

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    Selenium Biosorption and Recovery by Marine Aspergillus terreus in an Upflow Bioreactor
    (American Society of Civil Engineers (ASCE) onlinejls@asce.org, 2016) Raja, C.P.; Jacob, J.M.; Mohan Balakrishnan, R.M.
    Experiments were conducted to study the Selenium (Se) biosorption and recovery by marine Aspergillus terreus in an upflow bioreactor for a period of 8 days. The Se tolerance of the marine fungus was initially confirmed by visual and microscopic observations that evinced intact fungal cells in an Se-amended medium with sparse changes in the spore texture and cellular number by the seventh day of biosorption studies in the upflow bioreactor. Further, the effect of pH and contact time on the percentage of Se biosorption, in an upflow bioreactor containing fungal pellets, was investigated. It was analyzed that pH ranges of 6-7 and a contact time of 5 days resulted in 85-87% biosorption of Se by the fungal biomass. The interaction of the fungus with the induced Se stress in the medium was monitored regularly for studying the uptake of the metalloid and the possible biosynthesis of Se nanoparticles. Analyses using ultraviolet visible (UV-Vis) spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) studies revealed the formation of crystalline Se nanocrystals with an average diameter of 500 nm on the fungal cell wall. Fourier transform infrared (FTIR) spectroscopic analysis indicated the possible involvement of fungal protein groups that aid the binding of the biosorbed Se nanoparticles on to the fungal cell wall. © 2015 American Society of Civil Engineers.
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    Mycosensing of soil contaminants by Ganoderma lucidum and Omphalotus subilludens including the insights on growth media requirements
    (Elsevier Ltd, 2019) Gupta, C.; Mohan Balakrishnan, R.M.; Uddandarao, P.; Arivalagan, A.
    Heavy metals are regarded as one of the major threats to environmental biota due to prolonged soil residence time. In this scenario, mycoremediation emerged as an effective tool for the removal of heavy metal contaminants. The present study reports the responses of two wild mushroom species Ganoderma lucidum and Omphalotus subilludens under metal stress conditions and the nutritional requirements of the mushroom species. The media was screened wherein the media containing glucose and sucrose as carbon source showed better growth for Ganoderma lucidum and Omphalotus subilludens respectively. In addition, peptone as a nitrogen source is required for the growth of both Ganoderma lucidum and Omphalotus subilludens. Further, it is observed that macronutrients play a crucial role in the stimulation of enzymes and the micronutrients are mandatory for intermediary metabolism of the fungi in both the species. Tolerance studies are carried out in-vitro and the results reveal that the Ganoderma lucidum showed tolerance towards Cr (VI), Ni (II), Pb (II) and Cd (II) at maximum tolerant concentrations of 1000 mg/kg, 500 mg/kg, 100 mg/kg and 10 mg/kg, in case of, Omphalotus subilludens showed tolerance towards Cr (VI), Ni (II) and Pb (II) at maximum tolerant concentration of 700 mg/kg, 700 mg/kg and 500 mg/kg respectively. Moreover, FTIR spectral analysis indicated the presence of components like oxalic acid and thiol compounds during metal stress conditions. © 2019 Elsevier Ltd