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The potential of using activated Ficus Hispida L. as a new biosorbent for the removal of lead from aqueous solution was investigated. The isotherms, kinetics of lead biosorption for F. Hispida L. were evaluated. The results indicate that equilibrium was established in about 30 min. The effect of the pH was examined in the range of 2–10. The maximum removal obtained is at pH value 6.1. The dosage and size parameters were also evaluated to get optimum biosorption of lead. The maximum biosorption capacity at 30°C is 32.42 mg/g. The effect of temperature has been carried out at 30, 35, 40, and 45°C. The data obtained from biosorption isotherms of lead at different temperatures fit to linear form of langmuir biosorption equation followed by Temkin and Freundlich equations. Biosorption kinetics data were modeled using the pseudo-first- and pseudo-second order and Elvoich equation models. The results indicate that the pseudo-second-order model best describes biosorption kinetic data. The thermodynamic pa...

The Aspergillus niger was tested for its ability to produce invertase on natural agricultural residues. Orange peel was selected as substrate due to its high peak enzyme activity, the maximum invertase activity was obtained in preliminary studies by incubating flasks containing orange peel as substrate supplemented with sucrose (1.0% w/v), yeast extract (1% w/v), and 4 ml of A. niger conidial suspension for 96 hours at 30°C.