Mmabatho Peggy Mobo
Cape Peninsula University of Technology, South Africa
Title: Isolation and identification of cyanide tolerant bacteria from wastewater discharged from an electroplating plant in Cape town, South Africa
Biography
Biography: Mmabatho Peggy Mobo
Abstract
The pollution of water sources is one of the major challenges municipalities face worldwide. The industrial wastewater discharged into the municipal sewers often contains toxic substances. Electroplating industries contribute to the pollution of water sources with cyanide, cyanide metal complexes and heavy metals used in metal plating processes. This study aimed to isolate and identify cyanide tolerant bacteria from wastewater discharged from an electroplating plant in the Western Cape,South Africa which was suspected to be disposing its potentially hazardous wastewater into the municipal sewers. Bacteria were isolated from the biofilm and wastewater collected from the electroplating plant. Pure colonies were cultured on nutrient agar supplemented with 400 mg/L cyanide to test for tolerance. The most tolerant isolates (n = 4) were then cultured in nutrient broth supplemented with different concentrations of cyanide (0–200 mg/L) to study their growth patterns. The four isolates
where further characterized by employing the Gram and endospore staining methods. Biochemical tests, selective media and an automated method using the VITEK 2 Compact (Biomerieux) were used to confirm the identity of the isolates. Genomic DNA was extracted and was subsequently used as a template for Polymerase chain reaction (PCR) to amplify the 16S rRNA gene. The amplified PCR product was purified and used as template for sequence analysis. Two of the isolates were identified as Pseudomonas species and the other two as Bacillus species. The four methods used (biochemical testing, selective media, VITEK 2 compact and sequence analysis) could confirm 100% identity up to the genus level even though a few discrepancies in
identifying the species existed. The 16S rRNA gene was useful in identifying the genus of the unknown bacteria isolated from the wastewater. Further studies are however needed to study more genes to differentiate the species. The most tolerant isolates would in the future be tested for cyanide degradation and possible candidates for bioremediation of cyanide and metal cyanide
complexes from the effluent before discharging into the municipal sewer.