Heavy Metal Tolerant Comamonas species Isolated from Soil Sample in Tanjaro Region of Sulaymaniyah City - Iraq

Abstract

The Tanjaro region, located southwest of Sulaymaniyah city, is polluted with industrial effluents, wastewater, and importantly, heavy metals from the nearby city. From this area, Comamonas sp. was isolated. Comamonas sp. cells are gram-negative straight or curved rod shape, non-fermentative, and produce an orange color in the presence of sodium selenite. Comamonas sp. was identified by biochemical tests that were confirmed by the automated VITEK2 system. Comamonas sp. tolerated high concentrations of mercury and cadmium. Maximum tolerance concentration (MTC) demonstrated Comamonas sp.’s ability to tolerate 3 mM Cd, and 6 mM Hg and optimal uptake was at 30 °C, and pH 7. Inductively, coupled plasma - optical emission spectrometry (ICP-OES) showed Comamonas sp. was able to reduce 15.92% of Cadmium, and 30.05% of Mercury per 24 hours in culture media. Results of the current study demonstrated that the metal resistant Comamonas sp. has the potential ability to remove Cd, Hg, and play a significant role in future bioremediation bioprocess.