Biosurfactant produced from P. aeruginosa RB 28 was extracted, purified and characterized. Thin layer chromatography results showed that the extract contained two different compounds. The identification of the nature of the two compounds showed that they were glycolipids and rhamnose was the sugar moiety in these glycolipids. It was concluded that these compounds were rhamnolipids. The production of biosurfactant was started at late log phase and reached its maximal level (2.7 g L(-1)) at the stationary phase. Study of some rhamnolipid properties showed that sunflower oil, heptadecane and paraffin were efficiently emulsified and emulsions formed with vegetable oils (olive oil, corn oil and sunflower oil) were more stable than emulsions formed with hydrocarbons.

The presence of non-steroidal anti-inflammatory drugs, such as diclofenac (DCF), in the environment, is an emerging problem due to their harmful effects on non-target organisms, even at low concentrations. We studied the biodegradation of DCF by the strain D15 of Enterobacter hormaechei. The strain was isolated from an activated sludge, and identified as E. hormaechei based on its physiological characteristics and its 16 S RNA sequence. Using HPTLC and GC-MS methods, we demonstrated that this strain metabolized DCF at an elimination rate of 52.8%. In the presence of an external carbon source (glucose), the elimination rate increased to approximately 82%. GC-MS analysis detected and identified one metabolite as 1-(2,6-dichlorophenyl)-1,3-dihydro-2H-indol-2-one; it was produced as a consequence of dehydration and lactam formation reactions.

In a screening program for isolation of thermophilic lipase-producing bacteria, a number of thermophilic bacteria were isolated from desert soil from Baltim, Egypt. Among 55 isolates, a potent bacterial candidate (starin-5) was characterized and identified by biochemical and PCR techniques, based on 16S rRNA sequencing. Phylogenetic analysis revealed its closeness to geobacilli especially the thermophilic Geobacillus stearothermophilus with optimal growth and lipolytic enzyme activity at 60°C and pH 7.0. An inducible nature of lipolytic enzyme synthesis using glycerol and glucose was demonstrated. Approximately, 94-100% of the original activity was retained due to thermal stability of the crude enzyme after heat treatment for 15 min at 30-60°C. The enzyme retained 84.84% of its original activity during incubation at 70°C (pH 8.0) for 15 min. Lipase enzyme from G. stearothermophilus strain-5 was immobilized on various carriers and the most suitable carrier was chitin that showed 73.03% of activity yield.

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