TY - JOUR
T1 - Laccase-mediator system for enzymatic degradation of carbonaceous matter in the sequential pretreatment of double refractory gold ore from Syama mine, Mali
AU - Sakai, Ryotaro
AU - Mendoza, Diego M.
AU - Konadu, Kojo T.
AU - Cindy,
AU - Aoki, Yuji
AU - Hirajima, Tsuyoshi
AU - Ichinose, Hirofumi
AU - Sasaki, Keiko
N1 - Funding Information:
The authors appreciate the financial supports of JSPS KAKENHI JP19KK0135, and JSPS International Exchange Programs JPJSBP120196505, JPJSBP120219929, JPJSCCB20200003, which were provided to KS. Laccase (Y-120) was supplied by courtesy of Amano Enzyme Co. Ltd. DRGO from Syama mines, Mali was provided by courtesy of Prof. Jacques Eksteen at Curtin University.
Funding Information:
The authors appreciate the financial supports of JSPS KAKENHI JP19KK0135 , and JSPS International Exchange Programs JPJSBP120196505 , JPJSBP120219929 , JPJSCCB20200003 , which were provided to KS. Laccase (Y-120) was supplied by courtesy of Amano Enzyme Co. Ltd. DRGO from Syama mines, Mali was provided by courtesy of Prof. Jacques Eksteen at Curtin University.
Publisher Copyright:
© 2022 Elsevier B.V.
PY - 2022/6
Y1 - 2022/6
N2 - The sequential bio-treatment of refractory carbonaceous gold ore is a promising solution to recover gold effectively by environmentally friendly technology, which includes bio-oxidation of sulfide and biodegradation of carbonaceous matter by lignin-degrading enzymes. There are several drawbacks in enzyme treatment using cell-free spent medium (CFSM), including lignin peroxidase and manganese peroxidase from Phanerochaete chrysosporium, in particular the poor stability of enzyme activities. In the present work, laccase-mediator system (LMS) was applied for the degradation of carbonaceous matter in real gold ore to improve the efficiency of gold extraction as well as handling. The LMS was intended to be a great alternative process of CFSM with utilizing purified laccase in the presence of 1-hydroxybenzotriazole as a mediator. The application of LMS provided several advantages including not only greater stability, greater efficiency to degrade carbonaceous matter, better handling, much saving the treatment time, but also wider availability in laccase. In addition, replacing bio-oxidation with ferric chloride leaching as the dissolution path of sulfides facilitated avoiding the formation of jarosite and saving the required time. The gold recovery by cyanidation was improved from 41.5 ± 0.3% for the starting material to 81.3 ± 3.9% (n = 2) for the solid residues after the modified sequential pretreatment. This is correspondent to 86.3% of gold recovery for the extractable maximum gold excluding the enclosed gold in acid-insoluble silicates. The improved process involving LMS can be proposed with valuable advantages to fit a sustainable metallurgical technology of gold ores.
AB - The sequential bio-treatment of refractory carbonaceous gold ore is a promising solution to recover gold effectively by environmentally friendly technology, which includes bio-oxidation of sulfide and biodegradation of carbonaceous matter by lignin-degrading enzymes. There are several drawbacks in enzyme treatment using cell-free spent medium (CFSM), including lignin peroxidase and manganese peroxidase from Phanerochaete chrysosporium, in particular the poor stability of enzyme activities. In the present work, laccase-mediator system (LMS) was applied for the degradation of carbonaceous matter in real gold ore to improve the efficiency of gold extraction as well as handling. The LMS was intended to be a great alternative process of CFSM with utilizing purified laccase in the presence of 1-hydroxybenzotriazole as a mediator. The application of LMS provided several advantages including not only greater stability, greater efficiency to degrade carbonaceous matter, better handling, much saving the treatment time, but also wider availability in laccase. In addition, replacing bio-oxidation with ferric chloride leaching as the dissolution path of sulfides facilitated avoiding the formation of jarosite and saving the required time. The gold recovery by cyanidation was improved from 41.5 ± 0.3% for the starting material to 81.3 ± 3.9% (n = 2) for the solid residues after the modified sequential pretreatment. This is correspondent to 86.3% of gold recovery for the extractable maximum gold excluding the enclosed gold in acid-insoluble silicates. The improved process involving LMS can be proposed with valuable advantages to fit a sustainable metallurgical technology of gold ores.
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U2 - 10.1016/j.hydromet.2022.105894
DO - 10.1016/j.hydromet.2022.105894
M3 - Article
AN - SCOPUS:85130544560
SN - 0304-386X
VL - 212
JO - Hydrometallurgy
JF - Hydrometallurgy
M1 - 105894
ER -