Bioleaching of gold, copper and nickel from waste cellular phone PCBs and computer goldfinger motherboards by two <italic>Aspergillus niger</italic>strains

Abstract

In an effort to develop alternate techniques to recover metals from waste electrical and electronic equipment (WEEE), this research evaluated the bioleaching efficiency of gold (Au), copper (Cu) and nickel (Ni) by two strains of Aspergillus niger in the presence of gold-plated finger integrated circuits found in computer motherboards (GFICMs) and cellular phone printed circuit boards (PCBs). These three metals were analyzed for their commercial value and their diverse applications in the industry. Au-bioleaching ranged from 42 to 1% for Aspergillus niger strain MXPE6; with the combination of Aspergillus niger MXPE6 + Aspergillus niger MX7, the Au-bioleaching was 87 and 28% for PCBs and GFICMs, respectively. In contrast, the bioleaching of Cu by Aspergillus niger MXPE6 was 24 and 5%; using the combination of both strains, the values were 0.2 and 29% for PCBs and GFICMs, respectively. Fungal Ni-leaching was only found for PCBs, but with no significant differences among treatments. Improvement of the metal recovery efficiency by means of fungal metabolism is also discussed.

Gold Bioleaching from Printed Circuit Boards of Mobile Phones by Aspergillus niger in a Culture without Agitation and with Glucose as a Carbon Source

“…However, no significant differences (p ≤ 0.001) were observed between treatments with PCB residues and their corresponding biotic controls, at all sampling times. Our results are similar to those reported by Madrigal-Arias et al [30] for A. niger MXPE6 grown in culture media amended with PCB waste (but without agitation) for 14 days. Findings of both studies highlight the need for carbon sources to provide energy to support fungal metabolic functions and fungal biomass production under stressful conditions [37,38].…”

“…Strain A. niger MX7 grows faster (five days) than strain A. niger MXPE6 (seven days) when they are cultivated in a Petri dish with potato dextrose agar (PDA) at 25 • C. Another difference is that A. niger MXPE6 produces a yellow pigmentation when grown on PDA and A. niger MX7 does not produce any pigmentation. Both fungal strains were selected from previous bioassays focused on testing their tolerance to high concentrations of gold [30].…”

“…Other reports mention that Pseudomonas aeruginosa and Bacillus megaterium are able to recover up to 37% Au from PCB pulp [28,29]. In the case of filamentous fungi, there is little information, and it is mentioned that the Aspergillus niger consortium is capable of leaching Au (87%) from PCB in a culture with agitation [30].…”

Metal Recovery from the Mobile Phone Waste by Chemical and Biological Treatments

“…The leached metal concentration in aqua regia was analyzed via inductively coupled plasma-atomic emission spectroscopy (ICP-AES). [9][10][11][12][13]. Also, Brandl et al (2001) reported that bacteria such as Thiobacillus ferrooxidans and T. thiooxidans and fungi such as Aspergillus niger and Penicillium simplicissimum were able to mobilize high percentages of Cu, Sn, Al, Ni, Pb, and Zn particles from WEEE [13].…”

Bioreduction of precious and heavy metals by Candida species under oxidative stress conditions

“…Nowadays, the obtainment of pure metals by high-cost mineral treatments such as pyrometallurgical and hydrometallurgical processes (Marchant, 1985) has been substituted by less expensive biological procedures known as bioleaching (Vera et al, 2013). These procedures make use of a large diversity of microorganisms such as bacteria, archae and yeasts (Kelly et al, 1979;Hutchins et al, 1986;Norris and Parrott, 1986;Wiegel and Ljungdahl, 1986;Biryuzova et al, 1987;Kelly and Harrison, 1989;Rawlings and Kusano, 1994;Clark and Norris, 1996;Karamushka and Gadd, 1999;Norris et al, 2000;Brandl et al, 2001;Vera et al, 2013;Madrigal-Arias et al, 2015) resulting in the isolation of macroscopic forms of minerals. Contrary to macroscopic metals, nanoparticles (NPs) exhibit physical and chemical characteristics such as optical, electrical, magnetic, colligative and catalytic properties, that depend from the form, size and method of isolation (Lu et al, 2013).…”