Ourdia-Nouara Kernou, Kamelia Kerdouche , Pr. Nawel Boucherba , Pr. Khodir Madani2026-07-282026-07-2820222582-5917https://dspace.crtaa.dz/handle/123456789/150Jonesia denitrificans BN13 grows very well on a medium made out of agricultural byproducts like orange peel, esparto grass, and retam; the relative enzyme activity of these three substrates was 0.662, 0.711, and 0.835 U/ml, respectively First time xylanases were effectively extracted utilising aqueous two-phase system (ATPS) that had 3.5% PEG, 14% KH2PO4/K2HPO4, and 9% KI, The inclusion of cells resulted in much improved output from the system, which is based on the technology's ability to work on the basis of the assumption that proteins may be selectively partitioned between the two aqueous phases. In the culture medium that is based on orange peel, a yield of 72% of the enzyme activity is found in the upper phase with a partition coefficient of 2.75 and a purification factor of 1.38. In the medium that is based on alfa, 57.5% of the enzyme activity is located in the lower phase with a partition coefficient of 0.67 and a purification factor of 1.78. In the medium that is based on retam, a yield of 82% of the enzyme activity.enAqueous two phases systemXylanasesJonesia denitrificans BN13Citrus sinencisStipa tenacissimaRetama Raetam.Article