Xylene is a hydrophobic and aromatic organic compound widely used as a solvent in various industries and medical technologies. While its use is of a practical and economic significance, it is also considered as a highly toxic compound and a severe source of pollution, especially when it is discharged into nature. The aim of our study was to contribute toward xylene biodegradation using microorganisms that belong to the Streptomyces group. These microorganisms have been subject of an increasing interest in basic research and in biotechnology applications. Our current research is primarily focused on the biodegradation and removal of xylene using free and immobilized Streptomyces sp. AB1 strain, isolated from the Mitidja plain soils (north of Algeria). The follow up of xylene removal kinetics showed higher elimination rates in medium containing xylene as the sole source of carbon (200 and 300 mg l⁻¹). Biodegradation percentage varies between 80 and 99%. GC spectra showed changes during incubation time which is an indication of a microbial attack. Production of biodegradation metabolites was also detected in the medium. In a similar way, the Streptomyces sp. AB1 strain was encapsulated in sodium alginate beads, the result of these investigation shows high xylene removal rate (90%) from contaminated water and that Streptomyces sp. AB1 can regenerate sodium alginate beads without loss of sorption capacity.

The development of a new clean, easy to handle process with similar efficiency to that of the conventional process is one of the most important challenges in green chemistry investigation. In this study, a new hybrid process was investigated; coupling coagulation-flocculation with adsorption using abundant and natural bioproducts (Chitosan and Ammi visnaga). The Chitosan/Ammi visnaga (coagulation/adsorption) system was studied for its Brilliant Green dye removal capacity. This new technique seems to be a good alternative method for wastewater treatment, showing satisfactory results with high rates of elimination that range around 90 %.