American Journal of Microbiological Research
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American Journal of Microbiological Research. 2018, 6(1), 14-21
DOI: 10.12691/ajmr-6-1-3
Open AccessArticle

Microbial Recovery of Gold Metal From Untreated and Pretreated Electronic Wastes by Wild and Mutated Cyanogenic Bacillus megaterium

Alshehri A.N.Z.1,

1Department of Biology, University college in Al-Jummum, Umm Al-Qura University, Makkah, 21955, Saudi Arabia

Pub. Date: February 03, 2018

Cite this paper:
Alshehri A.N.Z.. Microbial Recovery of Gold Metal From Untreated and Pretreated Electronic Wastes by Wild and Mutated Cyanogenic Bacillus megaterium. American Journal of Microbiological Research. 2018; 6(1):14-21. doi: 10.12691/ajmr-6-1-3


Technology of biorecovery by Bacillus megaterium to obtain gold as a complex of gold-cyanide from electronic waste material (EWM) was done. The bacteria were subjected to pretreatment and mutation. The exist metals in solution were dissolved via the pretreatment, that way, contest for the cyanide ion from other metals was reduced. The bacteria were subjected to mutation to be able grow at pH 9, 9.5 and 10, where the pKa of HCN is 9.3, thereby, the cyanide ion concentration available for bioleaching was increased by alkaline pH. The new mutated bacteria from the pretreated EWM at 0.5% pulp density obtained gold of 17, 25 and 21% at pH 9, 9.5 and 10, respectively. Whereas the old unmutated bacteria that grow at pH 7, recovered 11%. The outcomes demonstrated that effectiveness of the mutated alkaline bacteria (B. megaterium) in gold biorecovery was more than normal physiological (pH 7).

gold metal bioleaching electronic waste mutation cyanogenic Bacillus megaterium

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[1]  Gramatyka, P., Nowosielski, R., Sakiewicz, P., 2007. Recycling of waste electrical and electronic equipment. J. Achiev. Mater. Manuf. Eng. 20 (1-2), 535-538.
[2]  Ramesh Babu, B., Parande, A.K., Ahmed Basha, C., 2007. Electrical and electronic waste: a global environmental problem. Waste Manag. Res. 25 (4), 307-318.
[3]  Greenpeace, 2005. The E-Waste Problem, Vol. 2013. Accessed on 11 June, 2017 the-e-waste-problem/.
[4]  ETBC, 2012. Electronics Take Back Coalition-Facts and Figures on E-Waste and Recycling. Accessed on 3 July, 2017.
[5]  Cui, J., Zhang, L., 2008. Metallurgical recovery of metals from electronic waste: a review. J. Hazard. Mater. 158 (2-3), 228-256.
[6]  Pham, V., Ting, Y.P., 2009. Gold bioleaching of electronic waste by cyanogenic bacteria and its enhancement with bio-oxidation. Adv. Mater. Res. 71, 661-664.
[7]  Korte, F., Spiteller, M., Coulston, F., 2000. The cyanide leaching gold recovery process is a nonsustainable technology with unacceptable impacts on ecosystems and humans: the disaster in Romania. Ecotoxicol. Environ. Saf. 46 (3), 241-245.
[8]  Krebs, W., Brombacher, C., Bosshard, P.P., Bachofen, R., Brandl, H., 1997. Microbial recovery of metals from solids. FEMS Microbiol. Rev. 20 (3-4), 605-617.
[9]  Bosecker, K., 1997. Bioleaching: metal solubilization by microorganisms. FEMS Microbiol. Rev. 20 (3-4), 591-604.
[10]  Kita, Y., Nishikawa, H., Takemoto, T., 2006. Effects of cyanide and dissolved oxygen concentration on biological Au recovery. J. Biotechnol. 124 (3), 545-551.
[11]  Faramarzi, M.A., Stagars, M., Pensini, E., Krebs, W., Brandl, H., 2004. Metal solubilization from metal-containing solid materials by cyanogenic Chromobacterium violaceum. J. Biotechnol. 113 (1), 321-326.
[12]  Brandl, H., Lehmann, S., Faramarzi, M.A., Martinelli, D., 2008. Biomobilization of silver, gold, and platinum from solid waste materials by HCN-forming microorganisms. Hydrometallurgy 94 (1), 14-17.
[13]  Mecucci, A., Scott, K., 2002. Leaching and electrochemical recovery of copper, lead and tin from scrap printed circuit boards. J. Chem. Technol. Biotechnol. 77 (4), 449-457.
[14]  Yamane, L.H., de Moraes, V.T., Espinosa, D.C.R., Tenório, J.A.S., 2011. Recycling of WEEE: characterization of spent printed circuit boards from mobile phones and computers. Waste Manage. (Oxford) 31 (12), 2553-2558.
[15]  Brandl, H., Bosshard, R., Wegmann, M., 2001. Computer-munching microbes: metal leaching from electronic scrap by bacteria and fungi. Hydrometallurgy 59 (2-3), 319-326.
[16]  Mishra, D., Rhee, Y.H., 2010. Current research trends of microbiological leaching for metal recovery from industrial wastes. Curr. Res. Technol. Edu. Top. Appl. Microbiol. Microb. Biotechnol. 2, 1289-1292.
[17]  Sum, E.Y.L., 1991. Recovery of metals from electronic scrap. JOM 43 (4), 53-61.
[18]  Kulandaisamy, S., Rethinaraj, J.P., Adaikkalam, P., Srinivasan, G., Raghavan, M., 2003. The aqueous recovery of gold from electronic scrap. JOM 55 (8), 35-38.
[19]  Ilyas, S., Anwar, M.A., Niazi, S.B., Afzal Ghauri, M., 2007. Bioleaching of metals from electronic scrap by moderately thermophilic acidophilic bacteria. Hydrometallurgy 88 (1-4), 180-188.
[20]  Liang, G., Mo, Y., Zhou, Q., 2010. Novel strategies of bioleaching metals from printed circuit boards (PCBs) in mixed cultivation of two acidophiles. Enzyme Microb. Technol. 47 (7), 322-326.
[21]  Xiang, Y., Wu, P., Zhu, N., Zhang, T., Liu, W., Wu, J., Li, P., 2010. Bioleaching of copper from waste printed circuit boards by bacterial consortium enriched from acid mine drainage. J. Hazard. Mater. 184 (1-3), 812-818.
[22]  Pant, D., Joshi, D., Upreti, M.K., Kotnala, R.K., 2011. Chemical and biological extraction of metals present in E waste: a hybrid technology. Waste Manage. (Oxford) 32 (5), 979-990.
[23]  Tuncuk, A., Stazi, V., Akcil, A., Yazici, E.Y., Deveci, H., 2012. Aqueous metal recovery techniques from e-scrap: hydrometallurgy in recycling. Miner. Eng. 25 (1), 28-37.
[24]  Hagelüken, C., Greinerstraat, A., 2005. Recycling of electronic scrap at Umicore’s integrated metals smelter and refinery. pp. 307-323.
[25]  Mudder, T.I., Botz, M., Smith, A., 2001. Chemistry and Treatment of Cyanidation Wastes. Mining Journal Books, London, UK.
[26]  Rajat, G., David, D., George, W.-C., 2005. Physical and chemical forms of cyanide. In: Cyanide in Water and Soil. CRC Press, pp. 15-23.
[27]  Faramarzi, M.A., Brandl, H., 2006. Formation of water-soluble metal cyanide complexes from solid minerals by Pseudomonas plecoglossicida. FEMS Microbiol. Lett. 259 (1), 47-52.
[28]  Chi, T.D., Lee, J., Pandey, B., Yoo, K., Jeong, J., 2011. Bioleaching of gold and copper from waste mobile phone PCBs by using a cyanogenic bacterium. Miner. Eng. 24 (11), 1219-1222.
[29]  Lawson, E., Barkhuizen, M., Dew, D., 1999. Gold solubilisation by the cyanide producing bacteria Chromobacterium violaceum. Process Metall. 9, 239-246.
[30]  Haque, K., 1992. The role of oxygen in cyanide leaching of gold ore. Can. min. metall. bull. 85 (963), 31-38.