Aluminum was bioextracted from black shale using Aspergillus niger and Penicillium notatum as acidophiles. Wet chemical and electron dispersive X-ray analysis (EDX) showed the presence of iron, silicon, aluminum, titanium, copper, sulphur, phosphorus, chlorine, potassium, sodium, calcium, carbon and oxygen in the original shale. A detailed investigation of the leaching process with these microorganisms was conducted. Microbes were tested for acid production and leaching capabilities of aluminum from black shale. Different organic wastes were evaluated as substrates by microbes. Moreover, citric acid generated by fungi could be an important leaching agent acting in the dissolution of aluminum. Aluminum dissolution with A. niger was better than those with P. notatum. Maximum recovery of aluminum (65.71%) was found in an A. niger medium containing acidified mango peel substrate at 28oC after 36days of leaching at 120 rpm. The results obtained with chemical leaching when using different concentrations of organic acids showed that dissolution of aluminum was much higher in citric and oxalic acid than other acids. Besides acidic metabolites production, microbiological activities play an important role in contribution of metals extraction. In future scenario, these discarded ores might be a potential source of metals.

Fozia Anjum, Shazia Anwer Bukhari, Tajnees Pirzada, Mir Munsif Ali Talpur, Mahmood-ur Rahman and Shahzad Ahmad Shahid Chatha