Reduction of hexavalent chromium by Ochrobactrum intermedium BCR400 isolated from a chromium-contaminated soil

Abstract

Hexavalent chromium-resistant Ochrobactrum intermedium BCR400 was isolated from chromium contaminated soil collected from Vadodara, Gujarat. It reduced 100 mg Cr(VI)/L completely in 52 h with initial Cr(VI) reduction rate of 1.98 mg/L/h. The Cr(VI) reduction rate decreased with increase in Cr(VI) concentration from 100 to 500 mg/L. The addition of anthraquinone-2-sulphonic acid (AQS) to culture O. intermedium BCR400 significantly enhanced its chromium reduction rate. The activation energy of AQS-mediated Cr(VI) reduction (120.69 KJ/mol) was 1.1-fold lower than non-mediated Cr(VI) reduction. An increase in the activities of quinone reductase and chromate reductase in cells grown in presence of AQS/AQS + Cr(VI) suggests their role in reduction of Cr(VI) by O. intermedium. Both chromate reductase and quinone reductase activities were FAD independent, required NADH as reductant, displayed maximum activity at pH (7.0) and temperature (30 °C). Thus Cr(VI) bioremediation potential of O. intermedium can be enhanced by augmentation of system with AQS as redox mediator.

Hexavalent chromate reduction by alkaliphilic Amphibacillus sp. KSUCr3 is mediated by copper-dependent membrane-associated Cr(VI) reductase

“…50 and 10 % of activity was detected at pH 9.0 and 10.0, respectively. Similar observations of the influence of pH on bacterial Cr(VI) reduction have been made by others (Mclean and Beveridge, 2001;Sultan and Hasnain 2007;Desai et al 2008a, b;Kavita and Keharia, 2012). Although Amphibacillus sp.…”

“…4). It has been reported the optimal temperature of Cr(VI) reduction to be in the range of 30-40°C (Megharaj et al 2003;Desai et al 2008a, b;Park et al 2000;Pal et al 2005;Kavita andKeharia, 2012 Xu et al 2012). However, chromate reductases from thermophilic Thermus scotoductus SA-01 (Opperman et al 2008) and Bacillus firmus KUCr1 (Sau et al 2010) have been recently identified with an optimum temperature of Cr(VI)-reduction at 65 and 70°C, respectively.…”

“…Hexavalent chromium [Cr(VI)] is produced as a byproduct of theses industrial process, and Cr(VI) containing wastewater have become a well recognized hazard in water pollution control due to the extremely toxic, mutagenic, and carcinogenic effect of Cr(VI) on the biological systems (Mclean and Beveridge 2001;Elangovan et al 2006;Xu et al 2012). Moreover, Cr(VI) has been listed as one of the 17 chemicals posing greatest threat to humans by United States Environmental Protection Agency (USEPA), (McCullough et al 1999;Kavita and Keharia 2012). Chromium exists mainly as two stable oxidation states, Cr(VI) and Cr(III), which differ completely in their physiochemical properties and toxicity (Ishibashi et al 1990).…”

Bacterial Reduction of Cr(VI) and Fe(III) in In Vitro Conditions

“…This strategy for chromium removal offers a high promise as a bioremediation strategy (Garg, Tripathi, and Srinath 2012). Kavita and Keharia (2012) also reported Cr(VI) reduction by Ochrobacterium intermedium BCR400 isolated from chromium-contaminated sites. They observed that a redox mediator known as anthraquinone-2-sulfonate (AQS) enhanced the reduction process of Cr(VI) many fold.…”

Isolation and characterization of a crude oil degrading bacteria from formation water: comparative genomic analysis of environmental Ochrobactrum intermedium isolate versus clinical strains

“…Strains of O. intermedium are associated with both human beings and the environment. Some strains are pathogens which cause infection (Möller et al, 1999;Apisarnthanarak et al, 2005); some live in environments polluted by chromium (Kavita and Keharia, 2012), lead (Waranusantigul et al, 2011), and tobacco waste (Yuan et al, 2007), etc.…”