Absorption and Reduction of Chromium by Fungi

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Absorption and Reduction of Chromium by Fungi D. V. Sriharsha1 · R. Lokesh Kumar1 · Savitha Janakiraman1 Received: 13 March 2020 / Accepted: 22 August 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020

Abstract Biosorption has gained increased attention as a reliable and proven technology for the remediation of industrial effluents rich in chromium. The present study was planned to isolate potential fungi from effluents contaminated sites and assess their efficiency for the absorption and reduction of chromium. Two species of Aspergillus and a species of Trichoderma which were isolated from contaminated sites and exhibited resistance to 10 mM of chromium on agar were chosen for the study. A biosorbent was designed by growing these fungal isolates on luffa sponge under shaken condition. The absorption and reduction of chromium, by the designed biosorbent was determined by Atomic Absorption Spectrophotometry and UV Visible Spectrophotometer. Actively growing fungi on luffa sponge showed better absorption (21%–25%) and reduction (28%–35%) capacity when compared to heat killed biosorbent in all fungi tested within 24 h of incubation. Interestingly, there was a liner increase in the absorption and reduction (85%–100%) of chromium by the biosorbent designed by using A. niger. Keywords  Chromium · Fungi · Luffa sponge · Biosorbent · Absorption and reduction Chromium being one of the toxic heavy metals which is often used as a raw material in various industries such as electroplating, tanning, metal finishing, petroleum refining, wood processing, nuclear power plant, textile and automobile parts (Pal 1997; Smith et al. 2002). Even though chromium exists in various valence state, the most stable ones in the environment are in the form of trivalent (Cr-III) and hexavalent (Cr-VI) (Smith et al. 2002). Chromium in its trivalent form serves as a micro nutrients in human diet and is non-toxic, whereas, hexavalent form is reported for its toxicity having mutagenic, teratogenic and carcinogenic effect on human (Marsh and McInerney 2001). Removal of hexavalent chromium from the environment or its reduction to less harmful trivalent form is very much essential in the present scenario. Conventional methods such as ion exchange, precipitation, chemical reduction, electrolysis have been employed to reduce the Cr (VI) concentration in the effluent. Although, these techniques have proven effective in removing chromium ions, they have their own significant disadvantages * Savitha Janakiraman [email protected] 1



such as high cost, high energy requirement, and generation of secondary sludge which are often difficult to dewater, and these techniques might not work effectively as the concentration of metal ions falls below parts per million range (Brady and Tobin 1995). Hence, there is always a need for the development of a low cost, effective and ecofriendly method to remediate the heavy metal pollution in the environment. In recent days, biosorption by microbes has been suggested to be a potential alternative me