Screening micro-organisms for cadmium absorption from aqueous solution and cadmium absorption properties of Arthrobacter nicotianae

Abstract

To obtain basic information on how microbial cells absorb cadmium from aqueous solution, we examined cadmium absorption in various micro-organisms. Of 51 micro-organism strains tested, we found that some Gram-positive bacteria, such as, Arthrobacter nicotianae and Bacillus subtilis, and some actinomycetes, such as, Streptomyces flavoviridis and S. levoris were highly capable of absorbing cadmium from an aqueous solution. A. nicotianae absorbed the largest amount of cadmium, over 800 μmol cadmium per gram of dry wt. cells. However, cadmium absorption by A. nicotianae was affected by the solution pH, cadmium concentration, and cell density. The absorption of cadmium was very rapid. Some factors that affected cadmium absorption by A. nicotianae cells were also discussed.

Graphical Abstract

We examined cadmium absorption of 51 microorganisms and found Arthrobacter nicotianae absorbed the largest amount of cadmium. Some factors that affected cadmium absorption by A. nicotianae cells were also discussed.

Key words:

• cadmium absorption
• desorption
• micro-organism
• Arthrobacter nicotianae
• immobilized cells

Acknowledgment

We wish to thank the graduated student Mr Yuki Aiba of Kyushu University for his measurements of the Zeta potential.