Food Waste-Assisted Metal Extraction from Printed Circuit Boards: The Aspergillus niger Route

Year: 2021

Authors: Alias C., Bulgari D., Bilo F., Borgese L., Gianoncelli A., Ribaudo G., Gobbi E., Alessandri I.

Autors Affiliation: Univ Brescia, LabNet Environm Sustainabil Lab B, Via Branze 45, I-25123 Brescia, Italy; Univ Brescia, Dept Mol & Translat Med, Agrifood & Environm Microbiol Platform PiMiAA, Via Branze 45, I-25123 Brescia, Italy; Univ Brescia, Dept Mech & Ind Engn, Chem Technol Lab, Via Branze 38, I-25123 Brescia, Italy; Univ Brescia, Dept Mol & Translat Med, AgroFood Lab, Piattaforma Proteom, Viale Europa 11, I-25123 Brescia, Italy; Univ Brescia, Dept Informat Engn, Via Branze 38, I-25123 Brescia, Italy; UdR Brescia, Consorzio Interuniv Nazl Sci & Tecnol Mat, Via Branze 38, I-25123 Brescia, Italy; UdR Brescia, Ist Nazl Ott INO CNR, Via Branze 38, I-25123 Brescia, Italy.

Abstract: A low-energy paradigm was adopted for sustainable, affordable, and effective urban waste valorization. Here a new, eco-designed, solid-state fermentation process is presented to obtain some useful bio-products by recycling of different wastes. Urban food waste and scraps from trimmings were used as a substrate for the production of citric acid (CA) by solid state fermentation of Aspergillus niger NRRL 334, with a yield of 20.50 mg of CA per gram of substrate. The acid solution was used to extract metals from waste printed circuit boards (WPCBs), one of the most common electronic waste. The leaching activity of the biological solution is comparable to a commercial CA one. Sn and Fe were the most leached metals (404.09 and 67.99 mg/L, respectively), followed by Ni and Zn (4.55 and 1.92 mg/L) without any pre-treatments as usually performed. Commercial CA extracted Fe more efficiently than the organic one (123.46 vs. 67.99 mg/L); vice versa, biological organic CA recovered Ni better than commercial CA (4.55 vs. 1.54 mg/L). This is the first approach that allows the extraction of metals from WPCBs through CA produced by A. niger directly grown on waste material without any sugar supplement. This green process could be an alternative for the recovery of valuable metals such as Fe, Pb, and Ni from electronic waste.

Journal/Review: MICROORGANISMS

Volume: 9 (5)      Pages from: 895-1  to: 895-10

More Information: This research wa s funded by MIPAAFT, Ministero Italiano per le Politiche Agricole, Alimentari, Forestali e del Turismo, grant RESTART project (Bando Sprechi 2019).
KeyWords: fungus; acid solution; organic waste; electronic waste; solid state fermentation; circular economy; valuable metals
DOI: 10.3390/microorganisms9050895

Citations: 9
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