Isolation and characterization of manganese solubilising bacteria and its potential for manganese bioleaching

摘要

Manganese minerals are widely distributed throughout the globe. The most important industrial uses of Mn are in the manufacture of steel, non-ferrous alloys, carbon-zinc batteries and some chemical reagents. The rich deposits with manganese concentrations in excess of 35% are preferred industrially, and lean deposits with manganese concentration less than 35% are presently ignored because extraction methods applied to rich manganese ore are not economically viable. Bioleaching is technologically feasible for extraction of manganese from low grade ores containing manganese less than 35% by weight. The recovery of manganese from low-grade manganiferous ores using bioleaching with different microorganisms is being increasingly applied for metal recovery. Biomineral extraction is considered as a better alternative as it holds the promise of lowering the fixed capital costs and of reducing environmental pollution which cannot be processed economically by conventional methods. Our study aims to isolate potential strain of manganese oxidising microflora from the low grade manganese ore deposits of Odisha, screen their manganese bioleaching capacity and to characterize them. In the present investigation, soil samples were collected from Joda manganese mine area. Serial dilution technique was followed to isolate indigenous manganese solubilising microorganisms from the soil sample. Nutrient agar media amended with MnO2 at concentrations ranging from 50 to 250 mg/L was carried out for the isolation of the Manganese oxidising bacterial strains. Two isolates capable of growing at varying MnO2 concentration are identified as Staphylococcus and Streptococcus by their physiochemical & morphological characters.