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8019284 
Journal Article 
Role of macro and micro elements on bioleaching of silica from Indian chromite ore by Aspergillus niger AB200 
Ball, D; Banik, AK 
2011 
Yes 
Journal of the Indian Chemical Society
ISSN: 0019-4522 
88 
9 
1355-1359 
English 
WOS:000295300400005 
Bioleaching of silica from chromite ore by Aspergillus niger AB(200) is performed to increase the chromium concentration in low grade chromite ore. The present study discuss about the role of nutritional factors necessary for the growth as well as bioleaching of silica from chromite. Besides carbon and nitrogen sources, the organism require macro elements like KH2PO4, KCl, MgSO4 center dot 7H(2)O, NaH2PO4 for their proper growth and silica bioleaching. Withdrawal of these elements from the fermentation media shows a significant decrease in both growth and bioleaching process. Elements like NaCl, CaCl2 were found to have no significant effect on growth of the organism and bioleaching process. Among the micro elements, Fe2+ and Mn2+ showed a significant increase in the bioleaching of silica from chromite ore. Zn2+, Ni2+ (below 10 mu g/ml) concentration and Cu2+ (below 5 mu g/ml) were found to have no significant effect, but with increase in concentration, all three elements were found to inhibit growth and bioleaching. Co2+, Mo6+, V3+ were found to have no significant role in this process. After optimization of the fermentation media (glucose - 10%, NaNO3 - 0.2%, KH2PO4 - 0.1%, KCl - 0.05%, MgSO4 center dot 7H(2)O - 0.06%, NaH2PO4 - 0.05%, FeSO4 center dot 7H(2)O - 15 mu g/ml, MnSO4 center dot H2O - 10 mu g/ml), 73.76% silica was found to be leached out from the ore. 
Silica; chromite ore; Aspergillus niger; bioleaching