(i) Formation of acidic liquids during bioleaching should be minimized or
avoided. This is because such acidic wastes pollute the environment and
harm ecosystems.
(ii) A crucial challenge in bioleaching processes is that they are time-consuming,
which hinders their practical success. Therefore, it is required to improve the
efficiency of bioleaching to the maximum extent. Additionally, combining
multiple effective techniques is an attractive choice.
(iii) When using extreme acidophiles, further investigation of EET pathways is
needed. Additional studies are required to understand whether or not specific
microorganisms have EET pathways. This is still very unclear.
(iv) Further studies are needed when exogenous ETMs participate in bioleaching.
This is to determine whether or not they can be reused or recycled.
(v) It is unknown whether or not specific acidophilic microorganisms can secrete
endogenous ETMs. If so, it may be possible to produce endogenous ETMs
using genetically engineered bacteria, thereby promoting bioleaching
efficiency.
References
Aarabi KM, Rashchi F, Mostoufi N, Vahidi E (2010) Leaching of vanadium from LD converter slag
using sulfuric acid. Hydrometallurgy 102:14–21. https://doi.org/10.1016/j.hydromet.2010.01.
006
Aditiawati P, Yohandini H, Madayanti F, Akhmaloka (2009) Microbial diversity of acidic hot
spring (Kawah Hujan B) in geothermal field of Kamojang Area, West Java-Indonesia. Open
Microbiol J 3:58–66. https://doi.org/10.2174/1874285800903010058
Appia AC, Guiliani N, Ratouchniak J, Bonnefoy V (1999) Characterization of an operon encoding
two c-type cytochromes, an aa3-type cytochrome oxidase, and rusti-cyanin in Thiobacillus
ferrooxidans ATCC 33020. Appl Environ Microbiol 65(11):4781–4787. https://doi.org/10.
1128/AEM.65.11.4781-4787.1999
Baker BJ, Banfield JF (2003) Microbial communities in acid mine drainage. FEMS Microbiol Ecol
44(2):139–152. https://doi.org/10.1016/S0168-6496(03)00028-X
Baker AC, Dopson M (2007) Life in acid: pH homeostasis in acidophiles. Trends Microbiol 15
(4):165–171. https://doi.org/10.1016/J.TIM.2007.02.005
Bhattacharyya A, Stavitski E, Dvorak J, Martinez CE (2013) Redox interactions between Fe and
cysteine: spectroscopic studies and multiplet calculations. Geochim Cosmochim Acta
122:89–100. https://doi.org/10.1016/j.gca.2013.08.012
Brandl H, Bosshard R, Wegmann M (2001) Computer-munching microbes: metal leaching from
electronic scrap by bacteria and fungi. Hydrometallurgy 59(2):319–326. https://doi.org/10.
1016/S0304-386X(00)00188-2
Brandl H, Lehmann S, Faramarzi MA, Martinelli D (2008) Biomobilization of silver, gold, and
platinum from solid waste materials by HCN-forming microorganisms. Hydrometallurgy 94
(1):14–17. https://doi.org/10.1016/j.hydromet.2008.05.016
Bryner LC, Anderson R (1957) Microorganisms in leaching sulfide minerals. Ind Eng Chem 49
(10):1721–1724. https://doi.org/10.1533/9781845694616.341
Cao B, Ahmed B, Kennedy DW, Wang Z, Shi L, Marshall MJ, Fredrickson JK, Isern NG, Majors
PD, Beyenal H (2011) Contribution of extracellular polymeric substances from Shewanella
sp. HRCR-1 biofilms to U(VI) immobilization. Environ Sci Technol 45(13):5483–5490. https://
doi.org/10.1021/es200095j
14 Heavy Metal Extraction from E-Waste Through Bioleaching: A Promising. . .
303
avoided. This is because such acidic wastes pollute the environment and
harm ecosystems.
(ii) A crucial challenge in bioleaching processes is that they are time-consuming,
which hinders their practical success. Therefore, it is required to improve the
efficiency of bioleaching to the maximum extent. Additionally, combining
multiple effective techniques is an attractive choice.
(iii) When using extreme acidophiles, further investigation of EET pathways is
needed. Additional studies are required to understand whether or not specific
microorganisms have EET pathways. This is still very unclear.
(iv) Further studies are needed when exogenous ETMs participate in bioleaching.
This is to determine whether or not they can be reused or recycled.
(v) It is unknown whether or not specific acidophilic microorganisms can secrete
endogenous ETMs. If so, it may be possible to produce endogenous ETMs
using genetically engineered bacteria, thereby promoting bioleaching
efficiency.
References
Aarabi KM, Rashchi F, Mostoufi N, Vahidi E (2010) Leaching of vanadium from LD converter slag
using sulfuric acid. Hydrometallurgy 102:14–21. https://doi.org/10.1016/j.hydromet.2010.01.
006
Aditiawati P, Yohandini H, Madayanti F, Akhmaloka (2009) Microbial diversity of acidic hot
spring (Kawah Hujan B) in geothermal field of Kamojang Area, West Java-Indonesia. Open
Microbiol J 3:58–66. https://doi.org/10.2174/1874285800903010058
Appia AC, Guiliani N, Ratouchniak J, Bonnefoy V (1999) Characterization of an operon encoding
two c-type cytochromes, an aa3-type cytochrome oxidase, and rusti-cyanin in Thiobacillus
ferrooxidans ATCC 33020. Appl Environ Microbiol 65(11):4781–4787. https://doi.org/10.
1128/AEM.65.11.4781-4787.1999
Baker BJ, Banfield JF (2003) Microbial communities in acid mine drainage. FEMS Microbiol Ecol
44(2):139–152. https://doi.org/10.1016/S0168-6496(03)00028-X
Baker AC, Dopson M (2007) Life in acid: pH homeostasis in acidophiles. Trends Microbiol 15
(4):165–171. https://doi.org/10.1016/J.TIM.2007.02.005
Bhattacharyya A, Stavitski E, Dvorak J, Martinez CE (2013) Redox interactions between Fe and
cysteine: spectroscopic studies and multiplet calculations. Geochim Cosmochim Acta
122:89–100. https://doi.org/10.1016/j.gca.2013.08.012
Brandl H, Bosshard R, Wegmann M (2001) Computer-munching microbes: metal leaching from
electronic scrap by bacteria and fungi. Hydrometallurgy 59(2):319–326. https://doi.org/10.
1016/S0304-386X(00)00188-2
Brandl H, Lehmann S, Faramarzi MA, Martinelli D (2008) Biomobilization of silver, gold, and
platinum from solid waste materials by HCN-forming microorganisms. Hydrometallurgy 94
(1):14–17. https://doi.org/10.1016/j.hydromet.2008.05.016
Bryner LC, Anderson R (1957) Microorganisms in leaching sulfide minerals. Ind Eng Chem 49
(10):1721–1724. https://doi.org/10.1533/9781845694616.341
Cao B, Ahmed B, Kennedy DW, Wang Z, Shi L, Marshall MJ, Fredrickson JK, Isern NG, Majors
PD, Beyenal H (2011) Contribution of extracellular polymeric substances from Shewanella
sp. HRCR-1 biofilms to U(VI) immobilization. Environ Sci Technol 45(13):5483–5490. https://
doi.org/10.1021/es200095j
14 Heavy Metal Extraction from E-Waste Through Bioleaching: A Promising. . .
303