This is a refereed journal and all articles are professionally screened and reviewed ORIGINAL A RTICLE Advances in Environmental Biology, 3(2): 204-209, 2009 ISSN 1995-0756 © 2009, American-Eurasian Network for Scientific Information 204 Corresponding Author A.S.Y. Ting, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Genting Kelang, Setapak 53300, Kuala Lumpur, Malaysia. Phone No. : 603-41079802; Fax No. : 603-41079803 E-mail: adelsuyien@yahoo.com; tingsy@utar.edu.my Utilization of Non-viable Cells Compared to Viable Cells of Stenotrophomonas Maltophilia for Copper (Cu(ii)) Removal from Aqueous Solutions A.S.Y. Ting and C.C. Choong Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Genting Kelang, Setapak 53300, Kuala Lumpur, Malaysia. A.S.Y. Ting and C.C. Choong.: Utilization of Non-viable Cells Compared to Viable Cells of Stenotrophomonas Maltophilia for Copper (Cu(ii)) Removal from Aqueous Solutions, Adv. Environ. Biol., 3(2): 204-209, 2009 ABSTRACT Stenotrophomonas maltophilia is an important bacterium in heavy metal bioremediation. Their application is however limited by the increasing reports of their pathogenic potential and resistance to common antibiotics. Therefore, non-viable cells present an interesting alternative as biosorbents. This study was conducted to investigate the potential of S. maltophilia in non-viable cell forms to remove copper (Cu(II)) from aqueous solutions. The total amount of Cu(II) removed by viable cells and adsorped by non-viable cells were compared and analyzed using equilibrium and kinetic models. Results showed that non-viable cells of S. maltophilia have higher efficacy in removing Cu(II) via surface sorption with 23.900 mg g Cu(II) adsorped compared to only -1 10.515 mg g dry biomass of Cu(II) removed by the viable cells. The adsorption mechanisms complied with -1 the Langmuir equilibrium model (R value of 0.9957) and the pseudo second order kinetic model (R value 2 2 of 1.000). Thus the adsorption was attributed to the functional groups on the cell wall via the monolayer adsorption capacity. Our study showed that non-viable cells of S. maltophilia can be applied and used more effectively than viable cell forms to remove Cu(II) from aqueous solutions. Key words: copper (Cu(II)), heavy metal pollutants, non-viable cells, Stenotrophomonas maltophilia, viable cells Introduction Copper (Cu(II)) is one of the six main metal ions with most immediate concern to the environment [1]. Copper pollution is ubiquitous in the environment, caused by the industrial effluents discharged from metal processing industries [2], from the electronic industries, and also from wastes derived from pharmaceutical and agricultural applications. High Cu(II) concentrations in waste water can easily seep into our water supply and food chain [3], causing acute Cu(II) poisoning in living organisms [4]. Early investigations have suggested that Cu(II) can be removed from the environment with the use of microorganisms tolerant to high levels of Cu(II) [5,6]. However, not all of these isolates can be readily introduced into the environment for intensive application as they may have pathogenic potential [7, 8] or are known to show resistance to common antibiotics [9]. As an alternative, non-viable cells (dead cells) of the tolerant strains can be studied for their potential in heavy metal removal, thus enabling the use of even strains with pathogenic potential. The removal of heavy metal like Cu(II) in dead cells is through the biosorption mechanism. The biosorption process is a passive and a metabolic independent process [10]. It takes place in the cell wall and the process is rapid and can remove a high percentage of cations (heavy metals). The efficacy of