Isolation and characterization mercury-resistant bacteria from gold mining in Lebong, Bengkulu

Abstract

Lebong a regency in Bengkulu Province, possesses prominent potential in gold mining. This mining activity is conducted through amalgamation techniques, resulting in the deposition of mining residue containing mercury, subsequently leading to environmental pollution. Recognizing the hazards associated with such pollution, it becomes imperative to mitigate the presence of mercury through effective remediation strategies. Bioremediation, utilizing Mercury Resistant Bacteria (MRB), widely known as a viable method for mitigating mercury contamination. This study aims to isolate and characterize MRB to facilitate their potential application in addressing heavy metal pollution. This study involved the isolation and characterization of MRB through morphological observations, Gram staining, and biochemical tests (glucose, sucrose, fructose, citrate utilization, starch hydrolysis, urease activity, and catalase production). A total of 43 bacterial isolates were obtained from water, sediment, and soil samples collected from surrounding gold mining waste disposal. Among these isolates, bacteria resistant to mercury were selected on NA supplemented with various concentrations of mercury. Five potential candidates of MRB were identified, with the highest mercury concentration tested being 1000 ppm. Based on identification using Bergey's Manual of Determinative Bacteriology, it was determined that four out of the five isolates belonged was Pseudomonas, while another belonged to Staphylococcus.