Shewanella baltica OS185

The Shewanellaceae are in general considered as of great value for bioremediation for sites contaminated with heavy metals or radioactive waste due to their ability to reduce the respective metal compounds.

OS185 is a highly versatile Shewanella baltica strain with respect to usage of electron acceptors and electron donors (Ziemke et al. 1998, Höfle et al. 2000). It is fast growing and easy to be cultivated and shows a fast onset of growth even after prolonged periods of starvation. It also shows good growth at low organic carbon concentration (Brettar et al. unpublished data). OS185 is a potential candidate to be used for bioremediation of sites contaminated with organic pollutants, heavy metals and for energy production in fuel cells.

OS185 was isolated in August 1986 from deep low oxic and nitrate rich water of  the Gotland Deep, a 240m deep anoxic basin in the Baltic Sea. OS185 forms part of a large scale collection and study on Shewanella-isolates from the water column of the central Baltic Sea. In this study it was shown that  Shewanella baltica had an increased abundance in the low oxic water and at the oxic-anoxic interface (Brettar & Höfle 1993, Brettar et al. 2001). According to clonal analysis of the population structure of Shewanella baltica by RAPD, OS185 formed part of a small clone (clone "C") that was present in the Baltic Sea in two subsequent years (only 6 out of 13 clones were present over two years) (Ziemke et al. 1997). Clone C is a highly versatile clone with respect to the use of electron donors.

The genome-sequenced S. baltica strains form part of different clones according to RAPD analysis that fits well with the physiological features, a coincidence that was interpreted as different niches occupied by the different clones (Höfle et al. 2000), Besides their potential use for biotechnological applications, the comparative genome analysis is targeted at a better understanding of the biogeochemical potential and the specific ecological niches of the different S. baltica- clones in the low oxic/anoxic water of the central Baltic Sea.

Recent studies in the central Baltic Sea showed that addition of complex organic matter can promote the rapid appearance of "blooms" of Shewanella baltica in the low oxic water of the Baltic Sea (Brettar et al., unpublished data). This potential of S. baltica for rapid growth even after prolonged starvation periods combined with the use of a broad range of different electron acceptors such as oxygen, nitrate, iron, sulfite, or thiosulfate can be of high relevance for the organic matter turnover in a stratified low oxygen environment like the central Baltic Sea.