Document Type : Original Article


Department of Microbiology, Faculty of Basic Sciences, Lahijan Branch, Islamic Azad University, Lahijan, Iran


Heavy metal pollution by natural factors is a world-wide phenomenon. Release of large quantities of heavy metals without handling proper processes that could decrease the concentration of such a material is a hassle that makes strains resistant to these heavy metals apart from entering into human food chain. In this research, wastewater of four firms in Guilan province such as Foolad, Risandegi, Chooka and Ganje tannery were analyzed according to standard methods. These methods were included culturing the strains on the specified media such as Luria-Bertani agar and Kings’ B. In the wastewater of these factories, there were kinds of heavy metals such as Chromium, Nickel, Cobalt, Mercury and etc. However existence of these heavy metals is fatal to keep the life progressive, but a kind of creatures like some bacteria could adapt themselves to the condition. Here we mentioned two genera of bacteria, Bacillus sp. and Pseudomonas sp., which were more renowned in the category of resistance to heavy metals. First of all, we used Nutrient Agar medium in order to distinction of Gram positive bacteria from Gram negative ones. After that, by dilution preparation from sample and inoculation the bacterial suspension into medium, the range of resistance to heavy metal concentration for Bacillus sp. in Luria-Bertani Agar and for Pseudomonas sp. in Kings’ B medium were determined. This estimation was validated by adding salt of heavy metal by the concentration from 0 µg/ml through 100 µg/ml and pH from 5 to 9. Results showed that both of two isolates had the most accumulation rate in pH=7 and concentration of 50 µg/ml heavy metal.


Brady, D., Glaum, D. and Duncan, J.R.,(1994). Copper tolerance in Saccharomyces cerevisiae. Lett. appl. Microbiol., 18:pp. 245-250.
Brieerle, C.L.,(1990). Bioremediation of metal contaminated surface and ground water. Geo-microbiol. J., 8:pp. 201-233.
Brown, D.L., et al. (2002). Mercury transport and resistance. Biochem. Soc. Trans., 30: pp. 715-718.
Chang, J.S., et al. (1998). Repeated fed-batch operations for microbial detoxification of mercury using wild-type and recombinant mercury-resistant bacteria. J. Biotechnol., 64:219-30.
Chipasa, K.B., (2003). Accumulation and fate of selected heavy metals in a biological wastewater treatment system. Waste Managem.23:pp. 135-143.
Chisti, Y.,(2004). Environmental impact of toxic pollutants. Biotechnol. Adv., 6: pp. 431-432.
COMPANY, R., et al. (2004). Effect of cadmium, copper and mercury on antioxidant enzyme activities and lipid per oxidation in the gills of the hydrothermal vent mussel Bathymodiolusazoricus. Mar. environ.
Res., 58: pp. 377-381.
Davis, T.A., Volesky, B. and Mucci, A., (2003). A review of the biochemistry of heavy metal biosorption by brown algae. Water Res., 37:pp. 4311-4330.
ESSA, A.M.M., et al. (2002).Mechanisms of mercury bioremediation. Biochem. Soc. Trans., 30:pp. 672-674.
Fortunato, R.,et al. (2005).Biodegradation of thiomersal containing effluents by a mercury resistant Pseudomonas putidastrain. Water Res., 15: pp.3511-3522.
Glendinning, K.J.,et al. (2005).Mercury tolerance of thermophilic Bacillus sp. and Ureibacillussp. Biotechnol. Lett. 27:pp. 1657-1662.
Gupta, A., Rai, V., Bagdwal, N. and Goel, R., 2005. In situ characterization of mercury-resistant growthpromoting fluorescent Pseudomonades. Microbial. Res., 160:pp. 385-388.
Hobman, J.L. and Brown N.L., (1997). Bacterial mercury-resistance genes. Met. Ions Biol. Syst., 34:pp.527-568.
Mindlin, S., et al.(2005). Present-day mercury resistance transposons are common in bacteria preserved in permafrost grounds since the Upper Pleistocene. Res. Microbiol., 156:pp.994-1004.
Miwa, K., et al. (1987). Long chained 1-mercapton-alkanes as potent inhibitors towards liver alcohol dehydrogenase. Biochem. biophys. Res. Commun., 142: pp.993-998.
Moore, B.,(1960). A new screen test and selective medium for the rapid detection of epidemic strains of Streptomyces aureus. Lancet, 11:pp. 453-458.
Perego, P. and Howell, S.B.,(1997). Molecular mechanisms controlling sensitivity to toxic metal ions in yeast. Toxicol. appl. Pharmacol., 147:pp. 312-318.
Reinhardt, C.A. and Pelli, D.A.,(1986). Screening for hepatotoxicity using freshly isolated and cryopreserved rat hepatocytes. Fd. Chem. Toxicol., 24:p. 576.
Romero, D., et al.(2004). Comparison of cytopathological changes induced by mercury chloride exposure in renal cell lines (VERO and BGM). Environ. Toxicol. Pharmacol., 17:pp.129-141.
Saha, D.K., et al. 2006. Mercury resistance in bacterial strains isolated from hospital and clinics. Bull. Environ. Contam. Toxicol. 77: pp.88-95.
Shakori, A.R., et al. (2002). Effect of mercuric chloride on liver function tests during regeneration following partial hepatectomy in rabbits. Proc. Pakistan Congr. Zool., 22:pp.145-156.
Wanger, D.,(2003). Pilot plant for bioremediation of mercury containing industrial wastewater. J. indust. Microbiol. 7:pp.1322-1327.
YUREIVA, O., et al.(1997). Intercontinental spread of promiscuous mercury-resistant transposons in environmental bacteria. Mol. Microbiol., 24:pp.321-329.
Zeroual, Y., et al. (2003). Biosorption of mercury from aqueous solution by Ulvalactucabiomass. Biores. Technol., 90:pp. 349-351.