Polarity of chloroform eluent critical to quantification of arbuscular mycorrhizal biomass in soil using the neutral lipid fatty acid biomarker C16:1cis11

Arbuscular mycorrhizal fungi (AMF) form mutualisms with the majority of terrestrial plants. The fatty acid biomarker C16:1cis11, abundant in the neutral lipids, has become the preferred method for quantification of AMF biomass within the soil. The neutral lipids are eluted from silica gel with chloroform; however, commercially available chloroform is stabilized with varying amounts of ethanol (0.5-1.9%) which influences its chromatographic properties. At ethanol contents below 1.0%, neutral lipids are being lost to the glycolipid fraction thereby underestimating AMF biomass in soil. Thus, quantification of AMF biomass in soil using C16:1cis11 found in neutral lipids is highly dependent on the chloroform used. Combining the neutral and glycolipid fractions is proposed as one alternative to address this issue.