BIOTECHNOLOGICAL STUDY ON HEAVY METALS ACCUMULATION BY SELECTED FRESH WATER BACTERIA USING BIOFILM SYSTEMS

Abstract

Trace quantities of many metals are important constituents of most waters however; many of these metals are also classified as priority pollutants.

Heavy metals are increasingly being released into the aquatic environment from different sources. The major source is the industrial effluents produced from different industries such as electroplating, tanning, refining, mining, pulp & paper....etc. that being discharged directly or indirectly into the aquatic environment. The present study aimed to investigate the capability of some selected or enhanced fresh water bacterial isolates to accumulate and remove some heavy

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metals (Fe, Cd, Pb, Cu and Zn) in a biofilm system that can be applied in a large

scale for the removal of heavy metals from the polluted effluents.

Four wild bacterial isolates; Bacillus licheniformis, Bacillus sphaericus, Arthrobacter sp. and Staphylococcus aureus previously isolated from Lake Mariut were selected and used during the present study for their known heavy - metals accumulative capacity.

The four selected bacterial isolates were used as immobilized cells attached to sand particles (mixed cultures biofilm system) in cylindrical plastic columns.