Screening and Identification of Rhizobacteria Isolated from Heavy Metal Contaminated Soils
Screening and identification of rhizobacteria isolated from heavy metal contaminated soils
INTRODUCTION As a result of human activities such as mining, agriculture and industrial activity, heavy metal pollution has become one of the most serious environmental problems today. Elevated levels of heavy metals not only decrease soil microbial activity and crop production, but also threaten human health through the food chain. Soil microorganisms can degrade organic contaminants, while metals need immobilization or physical removal. Although many metals are essential, all metals are toxic at higher concentrations, because they cause oxidative stress by formation of free radicals. Another reason why metals may be toxic is that they can replace essential metals in pigments or enzymes disrupting their function. Thus, metals render the land unsuitable for plant growth and destroy the biodiversity. Though several regulatory steps have been implemented to reduce or restrict the release of pollutants in the soil, they are not sufficient for checking the contamination. Metal contaminated soil can be remediated by chemical, physical and biological techniques. These can be grouped into two categories, ex-situ and in-situ method. One of the insitu method that has been used a lot to remediate heavy metal contamination is the phytoremediation method. Phytoremediation is the technology of remediation involving the use of green plants and their associated biota for treatment of contaminated soil. However, according to recent studies, the efficiency of metals uptake by plants used for phytoremediation can be enhanced by aid of plant promoting growth rhizobacteria. Therefore, main objective of this study is to identify tolerant heavy metals bacteria to be used in phytoremediation via supporting plants uptake of heavy metals in contaminated soils.
PROCEDURE A. Screening of rhizobacteria with heavy metal tolerant potential
Objective: To screen rhizobacteria tolerant to heavy
INTRODUCTION As a result of human activities such as mining, agriculture and industrial activity, heavy metal pollution has become one of the most serious environmental problems today. Elevated levels of heavy metals not only decrease soil microbial activity and crop production, but also threaten human health through the food chain. Soil microorganisms can degrade organic contaminants, while metals need immobilization or physical removal. Although many metals are essential, all metals are toxic at higher concentrations, because they cause oxidative stress by formation of free radicals. Another reason why metals may be toxic is that they can replace essential metals in pigments or enzymes disrupting their function. Thus, metals render the land unsuitable for plant growth and destroy the biodiversity. Though several regulatory steps have been implemented to reduce or restrict the release of pollutants in the soil, they are not sufficient for checking the contamination. Metal contaminated soil can be remediated by chemical, physical and biological techniques. These can be grouped into two categories, ex-situ and in-situ method. One of the insitu method that has been used a lot to remediate heavy metal contamination is the phytoremediation method. Phytoremediation is the technology of remediation involving the use of green plants and their associated biota for treatment of contaminated soil. However, according to recent studies, the efficiency of metals uptake by plants used for phytoremediation can be enhanced by aid of plant promoting growth rhizobacteria. Therefore, main objective of this study is to identify tolerant heavy metals bacteria to be used in phytoremediation via supporting plants uptake of heavy metals in contaminated soils.
PROCEDURE A. Screening of rhizobacteria with heavy metal tolerant potential
Objective: To screen rhizobacteria tolerant to heavy