Lead removal using industrially sourced consortia : influence of lead and glucose concentrations

Abstract

The objective of the current study was to explore the lead removal capabilities of two locally sourced industrial consortia using batch fermenters. The consortia were obtained from lead contaminated soil at a) a lead mine and b) an automotive battery recycling plant. The experiments were performed under anaerobic conditions using a rich growth medium (Luria Bertani Broth) with two different background lead concentrations (80 mg/L and 160 mg/L). The influence of added glucose to the medium was also studied. The residual aqueous lead was used as a measure of the lead removal capacity. Findings attest to the effectiveness of the industrially obtained consortia at removing lead from solution for both lead concentrations. Lead removal of between 91% and 93% in 168 hours and between 63% and 76% in 240 hours were achieved for the 80 mg/L and 160 mg/L experiments respectively. Minimal change was measured in the absorbances of these experiments, indicating a non-growth related lead removal mechanism. A glucose concentration of 60 g/L caused severe substrate inhibition which reduced the lead removal effectiveness to between 5% and 30% over a 214-hour period. The results for both consortia displayed significant similarities, indicating that analogous strains of organisms were present and active under the specific conditions.