الفهرس 
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Abstract
γ-Hexachlorocyclohexane (γ-HCH) and 4,4`-dibromodiphenylether (BDE) are halogenated pollutants that persist in the environment for a long time. These compounds are very difficult for bacteria and fungi to degrade. However, bacteria and fungi can cooperate within a community making the degradation process easier. The purpose of this work was to determine the extent of the microbial potential for the degradation of γ-HCH and BDE in soils. This study assessed the diversity of bacteria and fungi from 12 soil samples collected around insecticide and pesticide producing factories in Egypt. From γ-HCH and BDE enrichment cultures, all samples yielded highly diverse microbes as revealed by the analyses of the16S rRNA genes for bacteria and 18S rRNA genes for fungi. Soil and sediment samples were used to inoculate γ-HCH and BDE microcrystals on a substratum (PermanoxTM) in microcosms to grow complex biofilm communities on γ-HCH and BDE. The biofilms were monitored over 42 days by community fingerprinting using single strand conformational polymorphism (SSCP) of 16S rRNA and 18S rRNA gene amplicons. All soil samples yielded biofilms on γ-HCH & BDE and SSCP analyses of the biofilms revealed rather diverse bacterial and fungal communities. The structural biofilm development was monitored by Confocal Laser Scanning Microscope (CLSM) using Bac Light Kit, for LIVE (green) / DEAD (red) bacteria and Nile Red to stain hydrophobic compounds and revealed highly diverse biofilms with a dominance of damaged cell at the end of the incubation. From the soil samples, several species were obtained and most of them could use γ-HCH and BDE as sole source of carbon in a minimal medium. While many Gram-positive bacteria were isolated this group was almost absent in the different biofilm communities. Bacteria and fungi in microbial communities play different roles and together they are able to form biofilms using γ-HCH and BDE as a carbon source acting as a functional diversity cooperation.