Sulfurospirillum

Both the active enzyme, the heat-inactivated enzyme from Sulfurospirillum (Dehalos-pirillum) multivorans, and cyanocobalamin are capable of dehalogenating haloacetates (Nenmann et al. 2002), and the rate of abiotic dehalogenation depends on the catalyst that is nsed. 

Toxaphene is a complex mixture of compounds prepared by chlorinating camphene, and contains several hundred polychlorinated bornanes. After incubation with Sulfurospirillum (Dehalospirillum) multivorans only the hexa- (B6-923) and the heptachlorinated (B7-1001) remained. The nonachlorinated congener B9-1679 could be transformed by preferential dechlorination of the em-dichloro groups with formation of the heptachlorinated B7-1001 (Ruppe et al. 2003). Further examination showed that this congener could be dechlorinated to penta- and hexachlorinated bornanes (Ruppe et al. 2004). 

A comparison had been made of fractionation during the dechlorination of tetrachlo-roethene by Sulfurospirillum multivorans and Desulfitobacterium sp. strain PCE-S in laboratory experiments (Nijenhuis et al. 2005). Isotope fractionation in growing cultures was 1.0052 for Desulfitobacterium sp. and only 1.00042 for Sulfurospirillum multivorans, whereas fractionation was greater in crude cell extracts from both strains. It was concluded that caution should therefore be exercised in applying fractionation factors to the evaluation of in situ bioremediation. 

Arrangement is according to the atomic number of the reacting element. Currently Sulfurospirillum barnesii strain SES-3 (Stolz et al. 1999). Requires anthraquinine-2,6-disulfonate. 

A second example of a membrane-bound arsenate reductase was isolated from Sulfurospirillum barnesii and was determined to be a aiPiyi-heterotrimic enzyme complex (Newman et al. 1998). The enzyme has a composite molecular mass of 100kDa, and a-, P-, and y-subunits have masses of 65, 31, and 22, respectively. This enzyme couples the reduction of As(V) to As(III) by oxidation of methyl viologen, with an apparent Kra of 0.2 mM. Preliminary compositional analysis suggests that iron-sulfur and molybdenum prosthetic groups are present. Associated with the membrane of S. barnesii is a h-type cytochrome, and the arsenate reductase is proposed to be linked to the electron-transport system of the plasma membrane. 

Stolz JF, Ellis DJ, Blum JS, et al. 1999. Sulfurospirillum barnesii sp. nov. and Sulfurospirillum arsenophilum sp. nov., new members of the Sulfurospirillum clade of the e-Proteobacteria. Int J Syst Bacteriol 49 1177-80. 

The heme c nitrite reductase was isolated from anaerobes or facultative anaerobes like Desulfovibrio desulfuricans (ATCC 27774) [128], Wolinella suc-cinogenes [129], Escherichia coli [130], two Vibrio species [131,132] and Sulfurospirillum deleyianum [133]. In D. desulfuricans (ATCC 27774), W. succi-nogenes and S.deleyianum the enzyme is membrane-bound, and in the other cases it was isolated from the soluble fraction. 

It looks like, however, that the safe status of decaBDE might be soon reconsidered. Recent researches have shown that microorganisms present in North American and Enropean soil break down relatively stable decaBDE into octaBDE and then pentaBDE, both toxic. These microorganisms were identified as Sulfurospirillum and Dehalococcoides [10]. 

Structural WPC materials, 48 Struktol s TPW-113, 198 Struktol s TPW 104, 198 Styrene-acrylonitrile polymer, 91 Subterranean termites, 33 Sulfur-based antioxidants, 529 Sulfurospirillum, 472 Support span, 156, 228, 232, 233, 235,... 

Most of the above examples followed the dissolution of arsenic in complex sediment systems amended with scorodite and cultures of iron- or arsenate-respiring bacteria. More work was needed with simpler, defined systems to unravel the biological mechanisms from the adsorptive chemical phenomena. Zobrist et al. (43) studied the reductive dissolution of ferrihydrite that was coprecipitated with arsenate. Sulfurospirillum barnesii was the organism of choice because it respires both Fe(III) and As(V). Washed cell suspensions of S. barnesii simultaneously reduced Fe(III) as well as As(V) (Fig. 9). However, As(III) still had a... 

Figure 9 Reduction of As(V) and Fe(lll) in aggregates of arsenate coprecipitated with ferrihydrite by cell suspensions of Sulfurospirillum bamesii. (From Ref. 43.)...

Preliminary biochemical studies of the enzyme that catalyzes arsenate reduction in Sulfurospirillum barnesii have been conducted and the information only cited in two review articles (12,13). This enzyme is an integral membrane protein with a calculated mass of 100 kDa consisting of three different subunits 65, 31, and 22 kDa. The equivalent enzyme from Desulfomicrobium sp. str. Ben-RB (9) is discussed in Section III.D. The only respiratory arsenate reductase that has been studied in detail is that of C. arsenatis (14), discussed in Section II.D. 

Reductive Dehalogenases. Anaerobic microorganisms capable of reductive dechlorination of tetrachloroethylene, trichloroethylene, chlorinated phenols, and other chlorinated aromatics have recently been discovered and studied (10,53). The corrinoid reductase of Sulfurospirillum multivorans has been shown. 

---