Desorption of active cellulases from lignocellulosic substrates is a potential technique to reuse cellulases for the production of bioethanol. For desorption studies, adsorption of cellulases had to be performed first. Adsorption of cellulases NS 50013 onto microcrystalline cellulose (Avicel PH 101) and wheat straw lignin (Protobind 1000) was studied. It was found that Protobind adsorbed twice the amount of cellulases than Avicel did. An adsorption strategy developed was to work at pH 5 and a temperature less than 323 K to get maximum adsorption on the cellulose component, less adsorption on the lignin component of lignocellulosic materials, and to harmonize adsorption temperature with the industrial hydrolysis situation. Desorption of cellulases from Avicel and Protobind over a range of 298 K to 343 K and a pH of 6 to 9 was studied. Desorption obtained at pH 9 and 333K was optimum for both Avicel and Protobind. Hence, desorption was enhanced by 21 % and 11% for Avicel and Protobind respectively. The cellulases activity for Avicel was 48 FPU mL-1 at pH 9, 333 K, 5% glycerol, representing 91 % of the initial activity and for Protobind, the activity was 33 FPU mL-1 which represents about 66 % of the initial activity. All of these values were higher than ever reported in literature. At pH 5 and 298 K the amount of cellulases desorbed from untreated wheat straw (WS) was 33 % of those initially used for the adsorption step. It was increased to 42 % when 30 % delignified WS was used, and was further increased to 48 % for 60 % delignified WS. Desorption obtained for 60 % delignified WS was 75 % at pH 9, 333K and 5% glycerol. The desorption strategy recommended for bioethanol producing industries, is: 1) removal of lignin; 2) adsorption of cellulases at pH 5 and lower than 323K; 3) hydrolysis of lignocellulosic material; and 4) desorption of cellulases from non-hydrolyzed material at 333 K, pH 9, with 5-10 % glycerol. The proposed strategic desorption of cellulases may reduce the cost of Canadian bioethanol production by 26.5 % due to 75 % recyclability of active cellulases.

This study investigates the potential use of wheat straw (Tritium sativum) which is an agricultural by-product for the removal of Ni²⁺ and Zn²⁺ from the waste water discharges. Scanning Electron Microscope was used to obtain images of the surface of wheat straw (WS) and Electron Disperive Spectroscopy was employed in elemental analysis of wheat straw, Fourier Transform Infrared Spectroscopy was used to get informations about the chemcial interaction of the wheat straw surface with the sorbed metallic ions. Simulated wastewater containing Ni²⁺ and Zn²⁺ was subjected to biosorption by WS. The effect of initial concentration, pH and temperature on the removal of metal ions on WS was investigated. For varied initial metal concentrations from 5 to 150 ppm the biosorption equilibrium was achieved between 2.5 to 5 hours. The percentage removal of sorption decreases with increasing concentration. The experimental data were fitted to Langmuir, Freudlich and Temkin isotherms model fits better than the other two of single ionic system. For binary ionic system IAS-Freudndlich model served best. In addition the sorption by wheat straw conformed to pseudo second order kinetics with a good value of coefficient of determination (r² > 0.99). Free energy of biosorption ΔG°, enthalpy ΔH° and entropy ΔS° changes were also estimated and used to predict the nature of biosorption. The capacity of the sorption of wheat straw was compared with other common available sorbent. On the basis of sorption capacity, regenerate ability and the cost analysis we can conclude that WS could be used as a sorbent material for removal N²⁺ and Zn²⁺ from an aqueous solution.

Desorption of active cellulases from lignocellulosic substrates is a potential technique to reuse cellulases for the production of bioethanol. For desorption studies, adsorption of cellulases had to be performed first. Adsorption of cellulases NS 50013 onto microcrystalline cellulose (Avicel PH 101) and wheat straw lignin (Protobind 1000) was studied. It was found that Protobind adsorbed twice the amount of cellulases than Avicel did. An adsorption strategy developed was to work at pH 5 and a temperature less than 323 K to get maximum adsorption on the cellulose component, less adsorption on the lignin component of lignocellulosic materials, and to harmonize adsorption temperature with the industrial hydrolysis situation. Desorption of cellulases from Avicel and Protobind over a range of 298 K to 343 K and a pH of 6 to 9 was studied. Desorption obtained at pH 9 and 333K was optimum for both Avicel and Protobind. Hence, desorption was enhanced by 21 % and 11% for Avicel and Protobind respectively. The cellulases activity for Avicel was 48 FPU mL-1 at pH 9, 333 K, 5% glycerol, representing 91 % of the initial activity and for Protobind, the activity was 33 FPU mL-1 which represents about 66 % of the initial activity. All of these values were higher than ever reported in literature. At pH 5 and 298 K the amount of cellulases desorbed from untreated wheat straw (WS) was 33 % of those initially used for the adsorption step. It was increased to 42 % when 30 % delignified WS was used, and was further increased to 48 % for 60 % delignified WS. Desorption obtained for 60 % delignified WS was 75 % at pH 9, 333K and 5% glycerol. The desorption strategy recommended for bioethanol producing industries, is: 1) removal of lignin; 2) adsorption of cellulases at pH 5 and lower than 323K; 3) hydrolysis of lignocellulosic material; and 4) desorption of cellulases from non-hydrolyzed material at 333 K, pH 9, with 5-10 % glycerol. The proposed strategic desorption of cellulases may reduce the cost of Canadian bioethanol production by 26.5 % due to 75 % recyclability of active cellulases.

This study investigates the potential use of wheat straw (Tritium sativum) which is an agricultural by-product for the removal of Ni²⁺ and Zn²⁺ from the waste water discharges. Scanning Electron Microscope was used to obtain images of the surface of wheat straw (WS) and Electron Disperive Spectroscopy was employed in elemental analysis of wheat straw, Fourier Transform Infrared Spectroscopy was used to get informations about the chemcial interaction of the wheat straw surface with the sorbed metallic ions. Simulated wastewater containing Ni²⁺ and Zn²⁺ was subjected to biosorption by WS. The effect of initial concentration, pH and temperature on the removal of metal ions on WS was investigated. For varied initial metal concentrations from 5 to 150 ppm the biosorption equilibrium was achieved between 2.5 to 5 hours. The percentage removal of sorption decreases with increasing concentration. The experimental data were fitted to Langmuir, Freudlich and Temkin isotherms model fits better than the other two of single ionic system. For binary ionic system IAS-Freudndlich model served best. In addition the sorption by wheat straw conformed to pseudo second order kinetics with a good value of coefficient of determination (r² > 0.99). Free energy of biosorption ΔG°, enthalpy ΔH° and entropy ΔS° changes were also estimated and used to predict the nature of biosorption. The capacity of the sorption of wheat straw was compared with other common available sorbent. On the basis of sorption capacity, regenerate ability and the cost analysis we can conclude that WS could be used as a sorbent material for removal N²⁺ and Zn²⁺ from an aqueous solution.