Isolation and Identification of Cadmium Resistant Bacteria from Steel Factory Wastewater as biosorbents and their Ability

During the recent years, with the expansion of industrialization of the modern world, new methods of agriculture, and changes in climate conditions such as weathering, heavy metal pollution in the environment has increased. The accumulation of heavy metals in the ecosystem is extremely dangerous to the health human beings. For instance, Cadmium (Cd) is a heavy metal element and it is found to be exceedingly poisonous and carcinogenic. New techniques have been developed to rectify heavy metal contaminated sites. Among these methods, biosorption is proved to be more effective on a large scale. This study was performed to isolate the local bacteria, capable of biosorption of Cadmium, from the heavy metal contaminated sites. Based on the Minimum Inhibition Concentration (MIC) test, the bacteria most resistant to Cadmium (up to ۵۰۰۰ mg/l) was isolated from the strains in the Steel Factory wastewater was selected. This isolate was identified based on the morphological, physiological, phylogenetic, biochemical, and antibiotic resistance test characteristics as Pseudomonas sp. The effect of important parameters such as pH, temperature , and concentration bacteial biomass on the biosorption of Cadmium was studied. The optimum temperature and concentration of bacterial biomass for biosorption of cadmium were ۴۵ ° C and ۱.۵ g /l, respectively. The adsorption percentage was up to ۸۵%, with the highest adsorption rate seen at pH=۷. Pseudomonas sp. adsorption rate results were compared to other bacteria and their studies. It was concluded that the bacteria isolated from heavy metals contaminated had the high adsorption rate of Cadmium and and changing the pH parameter is more effective than other parameters. Pseudomonas sp. biomass can be a promising, efficient, cost effective, and ecofriendly way in the removal of Cadmium from the polluted environments.

کلیدواژه ها:

Local bacteria ، Minimum Inhibition Concentration test ، Pseudomonas ، pH