Fungal Leaching of Manganese Ore

Bioleaching is technologically feasible for extraction of manganese from low grade ores (containing manganese less than 35% by weight). The principle involves the non-enzymatic reduction of pyrolusite [Mn(IV) oxides] to +2 oxidation state by fungi with the production of metabolites such as oxalic acid and citric acid. In the present investigation, a fungal strain, Penicillium citrinum was isolated from top soil of Joda East manganese mine area, Tata Iron and Steel Company(TISCO), Orissa. Growth of the fungus was determined in terms of the final pH of the growth medium, biomass dry weight and total acid produced by the fungus. These data were used to evaluate the growth kinetics. Finally, it was used for bioleaching of low grade manganese ore. Effect of various parameters on in-situ leaching of manganese ore with P. citrinum such as (a) particle size (b) pulp density (c) sucrose concentration (d) inoculum size and (e) duration of leaching were studied. The maximum solubilisation of manganese (64.6%) was obtained with particle size of -45μm of the ore at pulp density of 2% (w/v), sucrose concentration 10% (w/v) and inoculum size of 10% (v/v) in a period of 30 days. of lowering the fixed capital costs and of reducing environmental pollution. The microbial leaching of manganese in general is carried out by heterotrophic microorganism which live in microaerobic conditions 3 and require one or more organic nutrients to serve as energy and carbon sources for their growth.