41 Electronic Journal of Environmental Sciences Vol. 2, 41-44 (2009) ISSN: 0973-9505 (Available online at www.tcrjournals.com) Original Article BIOACCUMULATION OF TRIVALENT CHROMIUM BY BACTERIA ISOLATE (CrRBI-1) SEPARATED FROM INDUSTRIAL EFFLUENT MISTRY, K., PATEL, J. AND BHAVSHAR, N. Ashok and Rita Patel Institute of Integrated Study & Research in Biotechnology and Allied sciences (ARIBAS), New Vallabh Vidyanagar 388 121 and Shree P.M Patel College of Paramedical Science and Technology, Anand 388 001. E. mail: kinnarinmistry@yahoo.com Received: May 15, 2009; Accepted: June 18, 2009 Abstract: Bioremediation technology has gained importance because microbes could be the convenient source of bio-absorption/bioaccumulation of metals from effluent streams. The chromium-resistant bacterial isolates (CrRBI-1) was selected from various bacterial separated from industrial effluent and grown in nutrient broth containing different concentrations of chromium chloride (0-12 mM) and their capability of accumulating metal from the medium. Well defined growth of CrRBI-1 was observed in the medium containing up to 9 mM of chromium. The isolate was identified using Biolog system. It was closely related to Curtobacterium pusillum. Maximum accumulation of trivalent chromium (347.54 mg/g dry weight of bacterial cells) was observed when CrRBI-1 was grown in media containing 12 mM of chromium. The protein profile of the CrRBI-1 cellular extract by SDS-PAGE showed one metal stress-induced proteins of molecular weight 33,000Da simultaneous down regulation of one protein of 33,000Da. Thus it is concluded that 33,000Da and 33,000Da proteins play a role in metal resistance mechanism by CrRBI-1 Key words: Bioaccumulation, Trivalent chromium, Curtobacterium pusillum ? INTRODUCTION Today indiscriminate and uncontrolled discharge of metal-contaminated industrial effluent in the environment has become an issue of major concern. Heavy metals are the important toxicants found in industrial waste water. Chromium toxicity is one of the major causes of environmental pollution emanating from tannery effluents. Chromium is used in nume- rous industries that invariably discharging the effluents in the environmental [1]. Chromium III plays a key role in the biological life in traces but above critical level it is toxic [2-4] mutagenic [5,6] carcinogenic [7,8] and tetrogenic [9]. Trivalent form of chromium is more common and its compounds are less soluble and toxic than hexavalent chromium. Trivalent chromium forms stable complex with legends on DNA, proteins and small molecules such as glutathisonein. Trivalent chromium bounds to the DNA template cause increased DNA polymerase processivity and decreased DNA replication fidelity. These alterations in DNA function can result in greatly increased bypass of oxidative DNA lesions, which are promutagenic. [10]. Chromium exists in several oxidation states (I–VI), more stable as Cr (III) and Cr (VI). Cr (VI) is the toxic form of the element [11] Cr (III) is also toxic at higher concentrations [12]. The permissible limit of total chromium in tannery effluents is between 1 and 2 mg/L according to USA, UK and Indian standards [13]. Chromium removal, to reduce the toxicity, is generally by chromium recovery [14,15], bioaccu- mulation, chromate reduction, chromate efflux [16], ion-exchange, coordination, complexation [1] and biosorption [17]. The objective of present study is isolate chromium (III) resistant microorganisms that are capable of resisting and surviving in these polluted environments and provides the knowledge for chromium bioremediation.