Bacterial populations and processes involved in acetate and propionate consumption in anoxic brackish sediment

Abstract

Bacterial populations and pathways involved in acetate and propionate consumption were studied in anoxic brackish sediment from the Grosser Jasmunder Bodden, German Baltic Sea. Uptake of acetate and propionate from the porewater was studied using stable carbon isotope‐labeled compounds. Labeled acetate was not produced as an intermediate during propionate uptake experiments, and propionate consumption was not affected by the addition of acetate. In parallel, incorporation of labeled acetate and propionate into phospholipid‐derived fatty acids (PLFA) was studied to indicate bacterial populations involved in the consumption of these substrates. The 13C‐acetate label was mainly recovered in even‐numbered PLFA (16:1ω7c, 16:0 and 18:1ω7c). In contrast, primarily odd‐numbered PLFA (a15:0, 15:0, 17:1ω6 and 17:0) and the even‐numbered i16:0 were labeled after incubation with 13C‐propionate. Although single PLFA labeled with propionate are commonly found in sulfate reducers, the complete PLFA‐labeling pattern does not resemble any of the know strains. However, the acetate‐labeling pattern is similar to Desulfotomaculum acetoxidans and Desulfofrigus spp., two acetate‐consuming, sulfate reducers. In conclusion, our data suggest that acetate and propionate were predominantly consumed by different, specialized groups of sulfate‐reducing bacteria.

Phospholipid fatty acid profiles at depositional and non-depositional sites in the North Sea

“…However, the use of 10Me16:0 as a specific biomarker for Desulfobacter spp. should done with care (Boschker et al 2001).…”

Methane as a carbon source for the food web in raised bog pools

“…Lipid analyses and stable-isotope analyses of PLFAs were done as described by Mohanty et al (2006). Lipids were extracted from 0.5 g of the BOM and 0.1 g of the invertebrate material with a Bligh-Dyer extraction procedure as modified and described by Boschker et al (1998Boschker et al ( , 2001). The lipid extract was fractionated on silicic acid into different polarity classes by sequential elution with chloroform, acetone, and methanol.…”

Stable Carbon Isotope Ratios of Lipid Biomarkers of Sulfate-Reducing Bacteria

“…Molecular genetic and physiological studies can indicate which SRB are present in an environment as well as their potential capabilities, but such studies do not determine which carbon transformations the SRB are actually carrying out in a particular environment. The use of stable-or radioisotope-labeled substrates can reveal flows and rates of transformations (2,3,26) but are limited in application, because their use might alter the natural abundance of key substrates and our ability to introduce these substrates into natural environments is limited. However, the study of stable isotopic compositions, at natural abundance, is a potential way to circumvent this problem and to determine the carbon substrates actually used by SRB.…”