원문정보
Characteristics of Dissimilatory Arsenate-reducing Bacteria
초록
영어
Although, microbial arsenic mobilization by dissimilatory arsenate-reducing bacteria (DARB) and the practical use to the removal technology of arsenic from contaminated soil are expected, most previous research mainly has been focused on the geochemical circulation of arsenic. Therefore, in this review we summarized the previously reported DARB to grasp the characteristic for bioremediation of arsenic. Evidence of microbial growth on arsenate is presented based on isolate analyses, after which a summary of the physiology of the following arsenaterespiring bacteria is provided: Chrysiogenes arsenatis strain BAL-1T, Sulfurospirillum barnesii, Desulfotomaculum strain Ben-RB, Desulfotomaculum auripigmentum strains OREX-4, GFAJ-1, Bacillus sp., Desulfitobacterium hafniense DCB-2T, strain SES-3, Citrobacter sp. (TSA-1 and NC-1), Sulfurospirillum arsenophilum sp. nov., Shewanella sp., Chrysiogenes arsenatis BAL-lT, Deferribacter desulfuricans. Among the DARB, Citrobacter sp. NC-1 is superior to other dissimilatory arsenate-reducing bacteria with respect to arsenate reduction, particularly at high concentrations as high as 60 mM. A gram-negative anaerobic bacterium, Citrobacter sp. NC-1, which was isolated from arsenic contaminated soil, can grow on glucose as an electron donor and arsenate as an electron acceptor. Strain NC-1 rapidly reduced arsenate at 5 mM to arsenite with concomitant cell growth, indicating that arsenate can act as the terminal electron acceptor for anaerobic respiration (dissimilatory arsenate reduction). To characterize the reductase systems in strain NC-1, arsenate and nitrate reduction activities were investigated with washed-cell suspensions and crude cell extracts from cells grown on arsenate or nitrate. These reductase activities were induced individually by the two electron acceptors. Tungstate, which is a typical inhibitory antagonist of molybdenum containing dissimilatory reductases, strongly inhibited the reduction of arsenate and nitrate in anaerobic growth cultures. These results suggest that strain NC-1 catalyzes the reduction of arsenate and nitrate by distinct terminal reductases containing a molybdenum cofactor. This may be advantageous during bioremediation processes where both contaminants are present. Moreover, a brief explanation of arsenic extraction from a model soil artificially contaminated with As (V) using a novel DARB (Citrobacter sp. NC-1) is given in this article. We conclude with a discussion of the importance of microbial arsenate reduction in the environment. The successful application and use of DARB should facilitate the effective bioremediation of arsenic contaminated sites.
목차
1. Introduction
2. DARB
2.1. Deferribacter desulfuricans SSM1 [21]
2.2. Chrysiogenes arsenatis BAL-1T [3,14]
2.3. Strains E1H and MLS10 [22,23]
2.4. Strain JMM-4 [24]
2.5. Bacillus sp. SF-1 [25,26]
2.6. Desulfitobacterium sp. GBFH [27]
2.7. Desulfitobacterium hafniense DCB-2T [27, 29]
2.8. Desulfotomaculum auripigmentum OREX-4 [13,30]
2.9. Citrobacter sp. TSA-1 [18]
2.10. Shewanella sp. ANA-3 [32]
2.11. Strain GFAJ-1 [33]
2.12. Strain MLMS-1 [34]
2.13. Desulfotomaculum sp. Ben-RB [35]
2.14. Sulfurospirillum barnesii SES-3T [8,10,36-38]
3. Characterization of Citrobacter sp. NC-1 in dissimilatory arsenate-reduction
3.1. Arsenate reduction by strain NC-1
3.2. Effect of other electron acceptors on arsenate reduction
3.3. Effects of electron donors on arsenate reduction
3.4. Arsenate and nitrate reduction by washed cell suspensions
3.5. Reductase activities in crude cell extracts
3.6. Inhibition of arsenate and nitrate reduction by tungstate
3.7. Extraction of As from contaminated forest soil
4. Perspectives
References