In this study, Bacterial cellulose (BC) grafted with Acrylic acid (AA) was prepared using Co 60 γ-rays source (30 KGy). Although many samples were prepared, BC: AA with ratio of 1:1 labelled as A1 and 2:1 labelled as A2 gave the most significant results. Hence these particular ratios have been selected and further investigated. AA was proven grafted onto BC by using ATR-FTIR due to the absent of CO stretching (1040 cm-1) in both hydrogels. The SEM image of both hydrogels samples showed highly porosity networks structure have been produced. The physical properties of the hydrogels such as equilibrium water content (%) and swelling ratio (%) in different pH buffer solution were measured. It was found that the equilibrium water content (%) of A1 was 93.10% while A2 was 74.83%, respectively. The results indicated that the equilibrium water content (%) increased by gaining the AA concentration. At pH10, the A2 swelling ratio (%) was two folded with 3350% in comparison with the A1. For the removal of methylene blue (MB) from aqueous solution, the results from the UV-VIS spectroscopy demonstrated that the A2 sample hydrogel was also an effective absorbent material.

Phosphorus (P) is one of the most essential macronutrients required for the growth of plants and is added to soil in the form of phosphatic fertilizers. However, because of mineral re-precipitation, large amount of applied phosphate fertilizer may become unavailable to the plant. The ability of soil microorganisms to transform insoluble forms of phosphorus to an accessible form is an important path in plant growth-promoting for increasing plant yields. In this study, Aspergillus Niger, a fungal strain isolated from agricultural soil samples, was tested for its ability to solubilize different phosphated matrixes (TCP, DCP, phosphates rock). The isolated fungus exhibits high capacities to solubilize all tested phosphates. The solubilization of insoluble phosphates was associated with a drop in the pH of the culture medium. The fungal biomass was entrapped in alginate and polyacrylamide gels and was used for solubilizing mineral phosphates in fluidized bed bioreactor. The highest specific solubilization rates were obtained when A. Niger was entrapped in alginate beads. The use of the bioreactor in consecutive cycles of solubilization showed the interest of the biomass immobilization in the stability of the bioreactor. Immobilized cells in alginate continuously solubilize phosphate even after 5 cycles of solubilization without loss of activity. The phosphorus biosolubilization performances of isolated strains may open new possibilities for their biotechnology application and allow the use of this fungus in the soil fertilization.

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