| Summary: | Tailing derived from gold mining have potential as hazardous pollutants to
the environment and human health, because it contains of various metal especially
mercury. The pollutants accumulated in the river bottom mixed with the river
sediment. The sediment is object of this research because it contains the tailings
used as the kemolitrotrof habitat especially bacteria resistant to mercury,
particularly methylmercury. It is highly toxic to all organisms, including
microbes, only a few types of bacteria able to survive and transforming the
metals into the less toxic forms. This research aims to obtain indigenus bacteria
resistant to methylmercury, and examine the capability of these bacteria grow in
several concentrations of methylmercury.
The research started with taking sediment samples containing gold mining
tailings as the bacterial source of methylmercury user. The methylmercury
utilizing bacteria were isolated through enrichment culture technique, using
column reactor filled with liquid medium of Nutrient Broth (NB), supplemented
with 0,1 mg/L CH3HgCl. After several sub-cultures, the bacteria were isolated
through dilution series and plated on Agar Nutrient (NA) containing 0.1g/L
CH3HgCl using pour plate techniques. The colonies growth separately was
taken and transferred on to agar slant as single culture. The isolate selection was
carried out based on their grow ability on various concentrations of CH3HgCl. At
time intervals, the bacterial growth was monitored spectrophotometrically
(λ600nm) and the total concentrations of mercury in the bacterial culture were
measured using an Atomic absorption spectrometer (AAS). Isolates having a short
of generation time (g) and the high growth rate (μ) were selected and identified
using standard Bergey�s Manual of Systematic Bacteriology.
The research results obtained thirteen isolates suspected as the
methylmercury user. Only three isolates (BPM-001, BPM-008 and BPM-008-
013) were able to grow relatively rapid as with by maximum specifik growth rate
(μmax) about 0,752/hour,thereby can be presumed the methilmercury has
inhibitor of the growth. The three isolates had been identified similar to Seratia
marcescen, (BPM-001), Psudomonas aeruginosa, (BPM-008) and Enterobacter
cloaceae, (BPM-013). These isolates were able to grow on methylmercury
concentration up to 4 mg/L.
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