The Research On Separation And Purification Of Endophytic Microorganisms From Solanum Nigrum L. And Removal Of Cd²⁺ By Them

Heavy metal is a kind of typical environmental pollutants. It is one of the hazards to water of the environment in recent years, and the form of very serious.Among the methods of treatment to heavy metal contamination, biosorption is a recent study, one of the most effective way. Solanum nigrum L.is reported Hyperaccumulator. It has short growth cycle, great biomass. It has characteristics as follows: strong ability of anti-adversity, absorbing water and nutrition; rapid growth, strong reproductive capacity, as well as in the appropriate conditions in circumstances it can dramatically increase the biomass. So it is a excellent material for phytoremediation. Endophytic microorganisms are microorganisms that live in plant tissues with out doing substantive harm and mediate various symbiotic reciprocities to theirs hosts. Endophytic microorganisms can produce a variety of active substances while living in plants, these substances can be the host plants have an enormous impact. The study found that endophytic microorganisms can promote the growth and competitiveness of the host. In agriculture, medicine, the healthy field endophyte has great potential applications as a biological control of resources, the foreign gene carriers and the source of new drugs.The endophytic microorganisms found widely in many kinds of plants mediate various effects to theirs hosts. In this study, 7 different dominant endophytes (SDE01 to 07) isolated from a Hyperaccumulator-Solanum nigrum L.were resistant to Cd2+, and the strain SDE06 survived even in the medium containing 80 mg/L of Cd2+. Bacteria strain SDE06 was identified as Bacillus sp..The removals of Cd2+ of SDE06 in different conditions were studied. Under the optimal conditions, the incubating time was 36 h, the solution pH6.0, the temperature was 37°C and the Cd2+ concentration of medium was 20 mg/L, the highest removal rate was up to 80.5% at this condition. After optimizing the separation and purification methods, 54 different endophytes isolated from Solanum nigrum L.