Background and objective: North Sulawesi is rich in minerals, among them gold is also present. The gold mining in the Buyat area produces heavy metal waste which can pollute the environment, among others is arsenic. Arsenic is a heavy metal that is very toxic to humans, so an agent is needed for the remediation process. The aim of this study was to isolate and identify arsenic-resistant bacteria from the Buyat estuary and beach to analyze the isolates' ability to detoxify arsenic.
Materials and methods: Soil sediment samples were obtained from Buyat estuary and beach in North Sulawesi. Isolation of arsenic-resistant bacteria was carried out by growing the samples in LB broth media containing 100, 500 and 1000 ppm arsenite. Indentification of arsenic-resistant bacteria was carried out by microbiological, biochemical and biomolecular analysis. The ability to detoxify arsenite was analyzed by CVAFS.
Results: The study showed that there were 4 isolates of arsenic-resistant bacteria isolated from the soil samples. All isolates are rod-shaped, Gram-negative and non-motile bacteria. BLAST results showed that isolates A was Stenotrophomonas sp., isolate B was Stenotrophomonas maltophilia, isolate C was Pseudomonas sp. and isolate D was Pseudomonas putida. All isolates reduced the levels of arsenic in media by almost 100% within 72 h.
Conclusion: The study suggested that Stenotrophomonas sp., S. maltophilia, Pseudomonas sp. and P. putida had the potentials to be used in the bioremediation of arsenic.
Keywords: Arsenic remediation; Buyat Bay; Buyat estuary; arsenic detoxification; arsenic-resistant bacteria.