UNAIR NEWS – The most dangerous heavy metal and considered a global problem for the environment and human health is mercury (Hg). In the environment, the entry of heavy metals is caused by natural processes, such as volcanic eruptions, rock weathering, atmospheric transportation, re-deposition, and human activities, such as coal burning, emissions from industrial processes, incineration, and industrial manufacture.
Several previous studies were carried out to isolate bacteria from contaminated areas. Bacteria found such as Pseudomonas sp., Bacillus sp., Acinetobacter sp., and Clostridium sp.
However, studies on the identification of mercury resistant bacteria from inactive sanitary landfills are still limited. Therefore, a lecturer of Faculty of Science and Technology (FST) Muhammad Fauzul Imron ST, MT conducted a research on the identification of bacteria isolated from inactive Keputih sanitary landfills and the characteristics of its resistance.
“Sanitary landfills are a source of mercury pollution because this area is used as battery disposal and some electronic devices. “Ground water contaminated with mercury in the sanitary landfill area is caused by the percolation of leachate containing heavy metals such as Hg, Cr, Fe, Mn, Mg, Zn, Pb, and Cd,” he explained.
Bacterial isolation in Keputih sanitary landfill, he added, was carried out by the serial dilution method following the previous research. Then, bacterial isolates with potential were identified.
Bacterial identification was carried out using biochemical characterization using a Microbact Identification Kit (MicrobactTM GNB 12A and 12B). The results of the identification kit are then analyzed based on Bergey’s Manual of Determinative Bacteriology.
“The bacteria that have been identified are then subjected to a resistance test with 4 different concentrations at 5, 10, 15 and 20 mg / L using the disk diffusion method against heavy metal Hg. The Minimum Inhibition Concentration (MIC) is determined based on the Inhibitory Zone Diameter (IZD) formed on the agar surface. Inhibited microbial activity was evaluated based on the diameter of the clear zone, “he said.
The identification results were in the form of potential bacteria of gram-negative, rod-shaped, oxidase-positive catalase, 92.74% compatible with the Pseudomonas fluorescens species. Mercury MIC for P. fluorescens is 5 mg / L. P. fluorescens has high resistance to mercury exposure.
“So from this study it can be seen that P. fluorescence isolated from the Keputih sanitary landfill has the potential to remove mercury in polluted areas. For further studies, the potential of P. fluorescens can be investigated to reduce areas contaminated with heavy metals with bioaugmentation and biostimulation techniques,” he concluded.
Author: Dian Putri Apriliani
Editor: Nuri Hermawan