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PLFA(Phospholipid Fatty Acid)

PLFAs are typical components of cell membranes. In sum, they form about 50 % of eukaryotic and even 98% of bacterial membrane lipids. In contrast to storage lipids, phospholipids’ content in bacterial cells is relatively constant over a wide range of growth conditions and they are quickly degraded after cell death (about two days under anaerobic and 12 to 16 days under aerobic conditions). Hence, PLFA analysis provides information leading to identification and quantification of viable bacterial biomass. PLFA analysis is more suitable for studies of viable organisms and provides a more consistent basis for descriptions of microbial community composition and characterization

PLFA analysis provides direct information on the entire microbial community in three key areas:

• PLFA is a primary component of the membranes of all microbes and decomposes quickly upon cell death, so total PLFA in a sample represents all "viable" cells. In many situations, an accurate measure of viable biomass is critical for evaluating microbial response to environmental conditions or treatments. With bioremediation for example, contaminant biodegradation rates are often proportional to biomass concentrations so site managers often use PLFA as one means to evaluate treatments. The opposite is also true. For drinking water applications, PLFA can be used to determine whether a treatment or disinfection process decreased viable biomass.

• Some organisms produce specific or signature types of PLFA biomarkers allowing quantification of important microbial functional groups (e.g. iron reducers, sulfate reducers, or fermenters). The relative proportions of these groups of PLFA biomarkers provide a fingerprint of the microbial community. This fingerprint can then be used to infer the overall response of the microbial community to a particular treatment.

• Some microbes, most notably Proteobacteria, modify specific PLFA biomarkers during periods of slow growth or in response to environmental stress. For example, cis monounsaturated fatty acids may be modified to cyclopropyl fatty acids during periods of slowed growth or modified to trans monounsaturated fatty acids to decrease membrane permeability in response to environmental stress. The ratio of product to substrate fatty acid thus provides an index of their health and metabolic activity.

In addition, PLFA analysis can be coupled to an innovative technique called Stable Isotope Probing (SIP) to show incorporation of a 13C labeled compound into microbial biomass thus conclusively demonstrating that biodegradation is occurring by showing label incorporation into biomass

PLFA analysis is an extremely robust technology with a long history that has been applied to nearly every specialty in the microbiology field including:

• Bioremediation Assessment


• Wastewater Treatment


• Drinking water Treatment


• Microbial Induced Corrosion


• Indoor Air Quality


• Bioreactors and more!

• Seal plates/tubes/slants with parafilm.
• Enclose samples in Ziploc plastic bags.
• Pack in a box with enough cushioning material.
• If refrigeration is required, package in an insulating material and include icepacks in zip loc bags.
• Include the completely filled Chain of Custody Form/Sample Submission Form.