Microbial community structure and activity in arsenic-, chromium- and copper-contaminated soils

Abstract

Microbial community structure, potential microbial activity and As resistance were affected by arsenic (As), chromium (Cr) and copper (Cu) contamination in soils of abandoned wood impregnating plants. Contaminated soils differed in the concentrations of soil acid-soluble and total water-soluble As, Cr and Cu, and in the concentration of bioavailable As analyzed with a bacterial sensor. Phospholipid fatty acid (PLFA) and 16S rRNA gene terminal restriction fragment length polymorphism (t-RFLP) profiles indicated that exposure to high metal contamination or subsequent effects of this exposure permanently changed microbial community structure. The total number of colony forming units (CFU) was not affected by metal contamination and the As(V)-resistant bacterial ratio to total heterotrophic plate counts was high (0.5-1.1) and relatively independent of the concentration of As. In contrast, the proportion of As(III)-resistant bacteria was dependent on the concentration of As in the soils and a significant positive relationship was found between the bioavailability of As and the proportion of As(III)-resistant bacteria. Dominant As-resistant isolates from contaminated soils were identified by their fatty acid methyl ester (FAME) profiles as Acinetobacter, Edwardsiella, Enterobacter, Pseudomonas, Salmonella and Serratia species. No differences were noted in glucose mineralization among contaminated and control soil samples within sites. Based on [(14)C]glucose mineralization the community was able to compensate for the reduced diversity. According to t-RFLP results, this was not due to a reversion towards the unexposed community, but mainly due to the appearance of new dominating species. This study, combining complementary culture-dependent and -independent methods, suggests that microbes are able to respond to soil metal contamination and maintain metabolic activity apparently through changes in microbial community structure and selection for resistance.

Dominance of sphingomonads in a copper-exposed biofilm community for groundwater treatment

“…EPS produced by bacteria frequently is responsible for biosorption of metals, providing sites for the binding of cations, and helping to protect the cells from damage (Bruins et al, 2000;Costley & Wallis, 2001;Teitzel & Parsek, 2003;Valls & De Lorenzo, 2002). Copper-resistant bacteria often produce large quantities of EPS (Turpeinen et al, 2004). Compared to the control treatment, the EPS composition of biofilms formed in the biofilter used in this study was altered in response to Cu(II), which drastically modified the carbohydrate/protein ratio (Table 2).…”

“…Metal stress results in decreased microbial diversity (Turpeinen et al, 2004). Copper often inhibits microorganisms, inducing the viable-but-non-cultivable condition (Ordax et al, 2006;Rensing & Grass, 2003); hence, cultivation-independent methods are required for the adequate study of the biological diversity of ecosystems exposed to high concentrations of this pollutant.…”

Effects of Experimental Lead Pollution on the Microbial Communities Associated with Sphagnum fallax (Bryophyta)

“…Indeed, the effects of heavy metals on microbial communities have been mostly studied in aquatic [11,21,34] and soil environments [33,40,42], whereas wetlands have been much less studied in this respect. Several studies have focused on the effect of metals and radionuclides on microorganisms in wetlands and some bacteria, and algae have been proposed to be used for removing these pollutants in wetlands [15,17,46].…”

Safety Assessment of Transgenic Organisms, Volume 4

“…DOCUMENTS ON MICRO-ORGANISMS SAFETY ASSESSMENT OF TRANSGENIC ORGANISMS: OECD CONSENSUS DOCUMENTS: VOLUME 4 © OECD 2010 other methods such as DNA typing methods (Turpeinen et al, 2004). Spectroscopic methods (Ruelle et al, 2004;Maquelin et al, 2005) discussed in section 2.3.4 were shown by some groups to have a very high power of resolution, that would make them suitable for strain differentiation and extremely promising in terms of scale-up.…”

“…Fatty acid profiling is still used in diagnostic laboratories to establish relatedness of different isolates (Glucksman et al, 2000;Kaiser et al, 2002;Hinton, Jr. et al, 2004), often in combination with other methods such as DNA typing methods (Turpeinen et al, 2004). Spectroscopic methods (Ruelle et al, 2004;Maquelin et al, 2005) discussed in section 2.3.4 were shown by some groups to have a very high power of resolution, that would make them suitable for strain differentiation and extremely promising in terms of scale-up.…”