Abstract
The fungi Aureobasidium pullulans, Mortierella humilis, Trichoderma harzianum and Phoma glomerata were used to investigate the formation of selenium- and tellurium-containing nanoparticles during growth on selenium- and tellurium-containing media. Most organisms were able to grow on both selenium- and tellurium-containing media at concentrations of 1 mM resulting in extensive precipitation of elemental selenium and tellurium on fungal surfaces as observed by the red and black colour changes. Red or black deposits were confirmed as elemental selenium and tellurium, respectively. Selenium oxide and tellurium oxide were also found after growth of Trichoderma harzianum with 1 mM selenite and tellurite as well as the formation of elemental selenium and tellurium. The hyphal matrix provided nucleation sites for metalloid deposition with extracellular protein and extracellular polymeric substances localizing the resultant Se or Te nanoparticles. These findings are relevant to remedial treatments for selenium and tellurium and to novel approaches for selenium and tellurium biorecovery.
Highlights
Selenium and tellurium are metalloids with chemical properties similar to sulfur, belonging to Group 16 of the Periodic table, and both commonly occurring in − II, + IV and + VI oxidation states (Eswayah et al 2016)
Little or no growth occurred in the presence of Na2SeO4, and only M. humilis and T. harzianum were able to grow on 1 mM Na2SeO4-amended malt extract agar (MEA)
This work has shown that A. pullulans, M. humilis, T. harzianum and P. glomerata were capable of reducing both selenite and tellurite to elemental selenium and elemental tellurium respectively
Summary
Selenium and tellurium are metalloids with chemical properties similar to sulfur, belonging to Group 16 of the Periodic table, and both commonly occurring in − II, + IV and + VI oxidation states (Eswayah et al 2016). Their related compounds, have drawn significant attention in recent years due to their properties of photoconductivity and thermoconductivity. They are classified as ‘E-tech’ elements and are essential components of photovoltaic solar panels, alloying agents, semiconductors and various electronic devices being used as, e.g. copper-indium-gallium-(di)selenide (CIGS) and cadmium telluride (CdTe) (Ramanujam and Singh 2017). Electrolytic refining employs a sulfate-based electrolyte to plate copper onto a cathode This electrolyte does not dissolve base metals which leads to accumulation of, e.g. gold, tellurium, selenium, bismuth, silver and other metals, along with various refractory components at the bottom of the electrolytic cells (George 2004; Bullock et al 2017). 15% of the 2700 tonnes of selenium produced each year is recycled, and most waste selenium products are discharged directly and/or indirectly into the environment, which may pose a threat to both aquatic and terrestrial environments and organisms (Haug et al 2007)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
