Aksu Z. | Yener J.

Article | 1998 | Process Biochemistry33 ( 6 ) , pp.649 - 655

The biosorption of phenol, o-chlorophenol and p-chlorophenol from aqueous solutions on dried activated sludge has been investigated. The pollutant binding capacity of the biosorbent was shown as a function of initial pH, initial pollutant concentration and substituted group. The maximum loading capacity of biosorbent was found to be 86.1 mg g-1 for phenol, 102.4 mg g-1 for o-chlorophenol and 116.3 mg g-1 for p- chlorophenol at 100 mg litre-1 initial pollutant concentration. The Freundlich and Langmuir adsorption isotherms were used for the mathematical description of the biosorption and the isotherm constants were evaluated for each . . . pollutant Daha fazlası Daha az

Bayramoğlu, Gülay | Hazer, Baki | Altıntaş, Begüm | Arıca, M. Yakup

Article | 2011 | Process Biochemistry46 ( 1 ) , pp.372 - 378

In this study, a functionalized hydrophobic polypropylene chloride membrane (PPC) was prepared by the amination of chlorinated polypropylene with hexamethylene diamine (APP). The PPC and APP membranes were characterized using SEM, FTIR and contact angle studies. The aminated polypropylene (APP) membrane was used for covalent immobilization of Candida rugosa lipase via glutaraldehyde coupling. The retained activity of the immobilized lipase was 76%. Kinetic analysis shows that the dependence of lipolytic activity of both free and immobilized lipase on tributyrin substrate concentration can be described by Michaelis-Menten model. The . . .estimated apparent Km values for the free and immobilized lipase were 2.9 and 8.4 mM, respectively. The Vmax values of free and immobilized enzymes were calculated as 926 and 741 U/mg enzyme, respectively. Optimal temperature was 5 °C higher for immobilized enzyme than that of the free enzyme. Thermal and storage stabilities were found to be increased upon immobilization. Finally, the immobilized lipase was used for the production of green apple flavor (i.e., ethyl valerate) in hexane medium. © 2010 Elsevier Ltd. All rights reserved Daha fazlası Daha az