Protecting drinking water: Rapid detection of human fecal contamination, injured and non-culturable pathogenic microbes in water systems

摘要

The rapid, potentially-automatable extraction of filter retentates has allowed quantitative detection of the unique biomarker for human fecal contamination, coprostanol, and the signature lipid biomarkers for total cellular biomass, viable cellular biomass, lipopolysaccharide (endotoxin). This method may be integrated with DNA based gene probe analysis for specific strains and enzyme activities. Not only does the analysis provide for detection of injured and non-culturable microbes but it also provides biomarkers characteristic of microbes exposed to biocides and disinfectants that can be utilized to monitor effectiveness of water mitigation/treatment. The analysis schemes involve filtration of the water or direct extraction of biofilms in sidestream chambers, supercritical fluid and/or liquid extraction, derivatization, and analysis of ''signature'' patterns by gas chromatography/mass spectrometry. Signature lipid biomarkers of interest are diglycerides, steroids including coprostanol and its isomers, poly-(beta)- hydroxyalcanoates (PHA), phospholipid ester-linked fatty acids (PLFA), and the lipopolysaccharide lipid A hydroxy fatty acids. PLFA found in polar lipid fractions estimate total viable cellular biomass, whereas the total cellular biomass can be calculated from diglyceride/phospholipid ester-linked fatty acids ratios. Furthermore, direct evidence of mitigation/treatment effectiveness can be ascertained by detection of diglycerides, respiratory quinones, PHA, and PLFA markers indicative of metabolic stress and toxicity such as trans monoenoic PLFA as well as oxirane and dicarboxylic fatty acids derived from the PLFA.