title: Purification and characterization of a highly active chromate reductase from endophytic Bacillus sp. DGV19 of Albizzia lebbeck (L.) Benth. actively involved in phytoremediation of tannery effluent-contaminated sites.
abstract: Phytoremediation using timber-yielding tree species is considered to be the most efficient method for chromium/tannery effluent-contaminated sites. In this study, we have chosen Albizzia lebbeck, a chromium hyperaccumulator plant, and studied one of its chromium detoxification processes operated by its endophytic bacterial assemblage. Out of the four different groups of endophytic bacteria comprising Pseudomonas, Rhizobium, Bacillus, and Salinicoccus identified from A. lebbeck employed in phytoremediation of tannery effluent-contaminated soil, Bacillus predominated with three species, which exhibited not only remarkable chromium accumulation ability but also high chromium reductase activity. A chromate reductase was purified to homogeneity from the most efficient chromium accumulator, Bacillus sp. DGV 019, and the purified 34.2-kD enzyme was observed to be stable at temperatures from 20°C to 60°C. The enzyme was active over a wide range of pH values (4.0-9.0). Furthermore, the enzyme activity was enhanced with the electron donors NADH, followed by NADPH, not affected by glutathione and ascorbic acid. Cu(2+) enhanced the activity of the purified enzyme but was inhibited by Zn(2+) and etheylenediamine tetraacetic acid (EDTA). In conclusion, due to its versatile adaptability the chromate reductase can be used for chromium remediation.
authors.affiliation: a Department of Bioresource and Food Science , Konkuk University , Seoul , South Korea.
authors.forename: Muthu
authors.initials: M
authors.lastname: Manikandan
authors.affiliation: a Department of Bioresource and Food Science , Konkuk University , Seoul , South Korea.
authors.forename: Judy
authors.initials: J
authors.lastname: Gopal
authors.affiliation: b Department of Biological Engineering , Konkuk University , Seoul , South Korea.
authors.forename: Rangarajulu Senthil
authors.initials: RS
authors.lastname: Kumaran
authors.affiliation: c Center for Advanced Studies in Botany , University of Madras, Guindy Campus , Chennai , India.
authors.forename: Vijayaraghavan
authors.initials: V
authors.lastname: Kannan
authors.affiliation: a Department of Bioresource and Food Science , Konkuk University , Seoul , South Korea.
authors.forename: Sechul
authors.initials: S
authors.lastname: Chun
mesh_terms: D031289:Albizzia / Q000378:metabolism / Q000382:microbiology; D001407:Bacillus / Q000201:enzymology* / Q000235:genetics; D001426:Bacterial Proteins / Q000302:isolation & purification / Q000378:metabolism; D001673:Biodegradation, Environmental; D002857:Chromium / Q000378:metabolism*; D060026:Endophytes; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D010088:Oxidoreductases / Q000302:isolation & purification* / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S; D012989:Soil Pollutants / Q000378:metabolism; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D012336:RNA, Ribosomal, 16S; D012989:Soil Pollutants; D002857:Chromium; D010088:Oxidoreductases; C063243:chromate reductase
keywords: Chromate reductase; chromium remediation; endophytic bacteria; phytoremediation; tannery effluent