title: Supercritical fluid extraction of microbial phospholipid fatty acids from activated sludge.
abstract: Supercritical carbon dioxide (scCO₂) extraction was applied for the determination of microbial phospholipid fatty acids (PLFA) in activated sludge. Quantification was performed by using gas chromatography-mass spectrometry (GC-MS). The highest extraction yields of PLFA, at a concentration of 7.28 nmol/mg-dry activated sludge, was obtained at a temperature of 80°C, pressure of 25 MPa and 10% (v/v) methanol for a 15-min extraction time. ScCO₂ extraction results obtained in these conditions were comparable with those obtained by liquid organic solvent extraction (LSE) based on diversity and equalibility indices. The repeatability test showed that the relative standard deviation values were less than 13%. The experimental results show that the scCO₂ extraction saves time and uses much less organic solvent. In addition, scCO₂ extraction is a promising and alternative method for the analysis of microbial community structure in environmental assessment using the PLFA profile.
authors.affiliation: Department of Ecological Engineering, Toyohashi University of Technology, Aichi 441-8580, Japan.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Hanif
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Atsuta
authors.forename: Koichi
authors.initials: K
authors.lastname: Fujie
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Daimon
mesh_terms: D002245:Carbon Dioxide / Q000737:chemistry; D025924:Chromatography, Supercritical Fluid / Q000379:methods*; D005227:Fatty Acids / Q000302:isolation & purification*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D000432:Methanol / Q000737:chemistry; D010743:Phospholipids / Q000302:isolation & purification*; D011312:Pressure; D015203:Reproducibility of Results; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology*; D012997:Solvents / Q000737:chemistry; D013696:Temperature
chemical_list: D005227:Fatty Acids; D010743:Phospholipids; D012722:Sewage; D012997:Solvents; D002245:Carbon Dioxide; D000432:Methanol