Isolation of Mercury Reducing Bacteria from Gold Mining waste that has the Potential as a Chromium Bioremediation Agent

Abstract

Traditional gold mining has been a widely handed down livelihood from the colonial era in Lebong regency, Bengkulu. Limited resources and low technology used on the gold mining has produce mercury waste that discharge to the environments directly. Over a long period of time, a unique bacteria community have been established in the mercury contaminated area. These bacteria can survive in the toxic metals’ environments. Bioremediation can be an alternative in dealing with environmental pollution by heavy metals. The goal of this research was to obtain morphological characterization of colonies and cell isolates of mercury reducing bacteria from the waste of gold miner for chromium bioremidiation. Bacterial isolation was carried out with nutrient agar (NA) media containing HgCl2 concentration of 0.01 ppm, 003 ppm, 0.05 ppm, 0.1 ppm and 0.2 ppm. The isolation results were selected from bacterial isolates that grew at HgCl2 concentrations. The selected isolates supported the independence of chromium with K2CrO4 concentrations of 10, 100 and 1,000 ppm. Then the morphology characterization of selected colonies and bacterial cells was carried out. The results of the study obtained 8 pure mercury reducing isolates. Only Sp8 bacterial isolates have the highest resistance to chrome to a concentration of 1,000 ppm. Bacteria Sp8 has the surface morphology of fine colonies, edges of circular colonies, flat elevation, overall appearance and color of yellowish white colonies and cell morphology with gram negative properties, basil cell shape, single cell arrangement and available endospores.