Bioleaching of manganese from mining waste residues using Acinetobacter sp.

S Ghosh,A P Das

doi:10.1080/24749508.2017.1332847

Abstract

The rapid decrease of natural resources and generation of huge amount of metallic wastes from mining industries has led to the focus of researchers to shift to alternative methods of waste benefaction and resource recycling. This study aims at the development of an eco friendly technique to recover Manganese (Mn) from mining waste residues using Acinetobacter sp. Bioleaching experiments were conducted in shake flasks at initial pH 6.5, 5% w/v inoculums and 2% pulp density at 30 °C with agitation speed 200 RPM and Acinetobacter sp. as inoculum. Mn recovery of 76% was recorded in 20 days. The analysis of the changes in cellular protein expression and conformation was carried out through sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS PAGE) and fourier transform infrared spectroscopy. The results reveal that bioleaching can alter protein expression and also result in conformational changes in protein structure. The present study sheds light on the greener alternative to recover and recycle manganese from wastes native bacteria. Exciting prospects for the utilization of mining wastes are in store in the near future; providing an economic and ecologically sound alternative to pyrometallurgical processes.

Highlights

The alignment of the present research focus on newer methods of metal extraction from secondary sources is rooted to the ever-growing global demand for metals (Mohanty et al, 2016a)
Due to the limitation of natural mineral sources and the huge wastage of minerals in form of mining wastes, the industries are in the pursuit of embracing newer, efficient and eco friendly alternatives for resource recycling (Das & Mishra, 2010)
Mn recovery of 76% was recorded in 20 days at initial pH 6.5, 2% w/v inoculums and 2% pulp density at 30 °C with agitation speed 200 RPM

Summary

Introduction

The alignment of the present research focus on newer methods of metal extraction from secondary sources is rooted to the ever-growing global demand for metals (Mohanty et al, 2016a). Due to the limitation of natural mineral sources and the huge wastage of minerals in form of mining wastes, the industries are in the pursuit of embracing newer, efficient and eco friendly alternatives for resource recycling (Das & Mishra, 2010). In comparison to the traditional metallurgical methods, bioleaching is less energy intensive and is environmentally friendly. It uses the inherent ability of microorganisms that enables them to convert insoluble conjugated minerals into their soluble and extractable forms (Chen et al, 2011; Das, Ghosh, Mohanty, & Sukla, 2015a). Direct mechanism involves the obtaining of electrons directly from the reduced elements. In this case, cell adhesion to the mineral surface is an absolute essential prerequisite. The indirect mechanism is mainly based on the production of metabolites like organic acid which in turn causes metal solubilization (Das, Pradhan, & Sukla, 2012; Das, Swain, Panda, Pradhan, & Sukla, 2012; Ghosh, Mohanty, Akcil, Sukla, & Das, 2016)

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