Attachment Behavior ofShewanella putrefaciensonto Magnetite under Aerobic and Anaerobic Conditions

Abstract

In this study, batch experiments were used to characterize attachment behavior of Shewanella putrefaciens strain 200R to ferrihydrite and magnetite. Attachment was quantified in batch experiments with a 0.01 M NaNO 3 solution as a function of pH (ranging from 3 to 10), sorbed anion (PO 3− 4 ), and growth conditions (aerobic vs. anaerobic). Electrophoretic mobility data was collected for S. putrefaciens cells and magnetite grains and used as a means to interpret the role of electrostatic interaction in attachment studies. Little difference in attachment behavior was observed as a function of growth conditions or surface treatments. The exception was at pH ranging from 2 to 4, under anaerobic conditions, where increased attachment was measured on magnetite surfaces with sorbed PO 3− 4 . This increased attachment was attributed to development of Fe-PO 4 surface complexes or secondary mineral phases, resulting in altered surface interactions between cell and mineral surfaces. Attachment was irreversible and increased with time under anaerobic conditions even under elevated pH conditions unfavourable to electrostatic interactions between cells and mineral surfaces. These results suggest that electrophoretic mobility data in this system is not a good predictor of attachment behavior, while surface charge development via protonation and deprotonation of surface functional groups is consistent with experimental attachment data. In this study, S. putrefaciens appears to utilize polymers or pili to remain attached to Fe-oxides and this process may facilitate Fe reduction on these surfaces. Results from this study underscore the need for quantitative bulk measurements of microbial attachment to accurately predict partitioning of dissimilatory iron reducing bacteria between solution and solid phases.

Mineral-microbe interactions: a review

“…Due to low solubility of phosphorous-containing mineral, such as apatite, phosphorous is often limited in natural environments. Thus, microbes preferentially colonize those mineral and rock surfaces that contain phosphorus, mostly apatite, olivine, feldspars, glass, and basalt to support growth (Bennett et al, 2001;Roberts, 2004;Rogers and Bennett, 2004;Roberts et al, 2006;Mauck and Roberts, 2007;Mailloux et al, 2009) (Fig. 1).…”

“…In earth surface environments where oxygen is abundant, aerobic microorganisms interact with oxide and silicate minerals to obtain essential nutrients and to use them as protection from lethal habitats. The production of surface polymers and siderophores help them attach and dissolve minerals as a way to extract nutrients (Liermann et al, 2000b;Maurice et al, 2000;Hersman et al, 2001a;Ams et al, 2002;Roberts et al, 2006;Maurice et al, 2009). In the subsurface conditions, where oxygen becomes limited, anaerobic microorganisms thrive by respiring oxidized forms of metals in place of oxygen (Lovley, 2000;Newman, 2001;Lloyd, 2002) with a consequence of either dissolving or precipitating minerals.…”

Early detection of oxidized surfaces usingShewanella oneidensisMR-1 as a tool

“…The two oxidized surfaces were topographically similar and appeared to be similar in color; however, MR-1 would not always rapidly recognize all of the surfaces ( Figure 5B). Although the rusted surfaces not rapidly bound by MR-1 appeared to be in the minority, these visual observations highlight the important point that MR-1, when grown under these conditions, did not bind rapidly to all forms of natural rust (Roberts et al 2006). …”

“…Consequently, proteins that interact with these oxides are located in the outer membrane. Given that only a few reports describing bacterial attachment to iron oxides have been published (Brown 1992;Ohmura et al 1993;Caccavo Jr. 1995;Lower et al 2001Lower et al , 2007Shaprio et al 2004;Parikh and Chorover 2006;Roberts et al 2006), a study was carried out to investigate the potential of iron oxide attaching bacteria to detect naturally formed rusted steel in situ. This communication reports the use of the dissimilatory iron-reducing bacterium, Shewanella oneidensis MR-1, known for its ability to interact with a variety of different iron oxides (Lower et al 2001(Lower et al , 2007Heidelberg et al 2002;Shapiro et al 2004), to rapidly and irreversibly attach to rusted surfaces and indicate early stages of oxidative activity on surfaces.…”

Characterization of Attachment and Growth ofThiobacillus denitrificanson Pyrite Surfaces

“…To date, research in microbial attachment to mineral surfaces has dealt mainly with adhesion of acidophilic iron-oxidizing bacteria (e.g., Acidithiobacillus ferrooxidans) to pyrite (e.g., Dziurla et al 1998;Edwards et al 1998;Harneit et al 2006;Mielke et al 2003;Ohmura et al 1993;Pisapia et al 2008;Solari et al 1992) and a few studies have assessed adhesion of iron-reducing bacteria (e.g., Shewanella oneidensis and Shewanella putrefaciens) to iron (oxy)(hydr)oxides (Neal et al 2003;Roberts et al 2006;Zhang et al 2010).…”