Cobalt Immobilization by Manganese Oxidizing Bacteria from the Indian Ridge System

Abstract

Co immobilization by two manganese oxidizing isolates from Carlsberg Ridge waters (CR35 and CR48) was compared with that of Mn at same molar concentrations. At a lower concentration of 10 μM, CR35 and CR48 immobilized 22 and 23 fM Co cell(-1) respectively, which was 1.4 to 2 times higher than that of Mn oxidation, while at 10 mM the immobilization was 15-69 times lower than that of Mn. Scanning electron microscope and energy dispersive X-ray analyses of intact bacterial cells grown in 1 mM Co revealed Co peaks showing extracellular binding of the metal. However, it was evident from transmission electron microscope analyses that most of the sequestered Co was bound intracellularly along the cell membrane in both the isolates. Change in morphology was one of the strategies bacteria adopted to counter metal stress. The cells grew larger and thus maintained a lower than normal surface area-volume ratio on exposure to Co to reduce the number of binding sites. An unbalanced growth with increasing Co additions was observed in the isolates. Cells attained a length of 10-18 μm at 10 mM Co which was 11-15 times the original cell length. Extensive cell rupture indicated that Co was harmful at this concentration. It is apparent that biological and optimal requirement of Mn is more than Co. Thus, these differences in the immobilization of the two metals could be driven by the differences in the requirement, cell physiology and the affinities of the isolates for the concentrations of the metals tested.

Immobilisation of manganese, cobalt and nickel by deep-sea-sediment microbial communities

“…However, the yield of cultured Ni-tolerant bacteria might correlate with the yield of Co-tolerant bacteria (r = 0.606, p < 0.05), suggesting that the same microbial communities are capable of immobilising both metals. These results agree with our recent reports [4,56] on Ni and Co immobilisation by Mnoxidising bacterial isolates from the Indian Ridge system. TBC correlated positively (r = 0.868, p < 0.001) and TOC negatively with depth (r = 0.666, p < 0.05).…”

Análisis geoquímico (elementos mayores, menores, traza, δ13C, δ18O y tierras raras) de microbialitas selectas provenientes de la Formación San Casiano (Triásico Medio - Superior, NE de Italia)

“…Algunos elementos con un posible efecto vital como el V (Robson et al, 1986), Cr (Congeevaram et al, 2007), Sn (Moser et al, 2009), Sb (Bentley y Chasteen, 2002), Zn (Sugarman, 1983), Cu (Mathews et al, 1999), Mo (Tucker et al, 1997;Dos Santos y Dean, 2008), Co (Hebbeln y Eitinger, 2004;Anthony et al, 2011) y Ni (Krüger et al, 2003;Hebbeln y Eitinger, 2004) presentan concentraciones significativas en todas las facies carbonatadas estudiadas (e.g. Kamber y Webb, 2007).…”

Changes in morphology and metabolism enable Mn‐oxidizing bacteria from mid‐oceanic ridge environment to counter metal‐induced stress

“…Thus, it was able to maintain lower than normal surface area-volume ratio perhaps to reduce the number of metal binding sites [30]. Interestingly, we observed deposition of globular particles of ∼180 nm in size on/around cells of M. algicola at ≥10 mmol Mn (II) L −1 ( Figure 4F) with complete encrustation of cells on a 10-fold increase of Mn (II) ( Figure 4G).…”