What do the PLFA structural groups represent?
- Date added:
- Thursday, 05 February 2009
Answer
The PLFA in a sample can be separated into particular types, and the resulting PLFA “profile” reflects the proportions of the categories of organisms present in the sample. Because groups of bacteria differ in their metabolic capabilities, determining which bacterial groups are present and their relative distributions within the community can provide information on what metabolic processes are occurring at that location. This in turn can also provide information on the subsurface conditions (i.e. oxidation/reduction status, etc.). The following table describes the six major structural groups used and their potential relevance to site specific projects.
|
PLFA Structural Group |
General classification |
Potential Relevance to Bioremediation Studies |
|
Monoenoic (Monos) |
Abundant in Proteobacteria (Gram negative bacteria), typically fast growing, utilize many carbon sources, and adapt quickly to a variety of environments. |
Proteobacteria is one of the largest groups of bacteria and represents a wide variety of both aerobes and anaerobes. The majority of Hydrocarbon utilizing bacteria fall within the Proteobacteria |
|
Terminally Branched Saturated (TerBrSats) |
Characteristic of Firmicutes (Low G+C Gram-positive bacteria), and also found in Bacteriodes, and some Gram-negative bacteria (especially anaerobes). |
Firmicutes are indicative of presence of anaerobic fermenting bacteria (mainly Clostridia/Bacteriodes-like), which produce the H2 necessary for reductive dechlorination. |
|
Branched Monoenoic (BrMonos) |
Found in the cell membranes of micro-aerophiles and anaerobes, such as sulfate- or iron-reducing bacteria |
In contaminated environments high proportions are often associated with anaerobic sulfate and iron reducing bacteria. |
|
Mid-Chain Branched Saturated (MidBrSats) |
Common in sulfate reducing bacteria and also Actinobacteria (High G+C Gram-positive bacteria). |
In contaminated environments high proportions are often associated with anaerobic sulfate and iron reducing bacteria. |
|
Normal Saturated (Nsats) |
Found in all organisms. |
High proportions often indicate less diverse populations. |
|
Polyenoic |
Found in eukaryotes such as fungi, protozoa, algae, higher plants, and animals. |
Eukaryotic scavengers will often prey on contaminant utilizing bacteria. |
