A carbon free filter for collection of large volume samples of cellular biomass from oligotrophic waters

• Published in: Journal of microbiological methods 2012-09, Vol.90 (3), p.145-151
• Main Authors: Mailloux, Brian J., Dochenetz, Audra, Bishop, Michael, Dong, Hailiang, Ziolkowski, Lori A., Wommack, K. Eric, Sakowski, Eric G., Onstott, Tullis C., Slater, Greg F.
• Format: Article
• Language: English
• Subjects: Aluminum - chemistry; Biological and medical sciences; Biomass; carbon; Carbon - chemistry; Carbon Radioisotopes - chemistry; Carbon Radioisotopes - metabolism; Escherichia coli; Escherichia coli - chemistry; Escherichia coli - metabolism; Fatty Acids - chemistry; Fatty Acids - isolation & purification; Fatty Acids - metabolism; Filter; filtration; Filtration - instrumentation; Filtration - methods; Fundamental and applied biological sciences. Psychology; Glass - chemistry; glass fibers; Groundwater - microbiology; laboratory techniques; Microbiology; Microscopy, Electron, Scanning; Microspheres; phospholipid fatty acids; Phospholipids - chemistry; Phospholipids - isolation & purification; Phospholipids - metabolism; PLFA; Radiocarbon; sand; Silicon Dioxide - chemistry; Water Microbiology; X-Ray Diffraction
• ISSN: 0167-7012; 1872-8359
• DOI: 10.1016/j.mimet.2012.04.016

Isotopic analysis of cellular biomass has greatly improved our understanding of carbon cycling in the environment. Compound specific radiocarbon analysis (CSRA) of cellular biomass is being increasingly applied in a number of fields. However, it is often difficult to collect sufficient cellular biomass for analysis from oligotrophic waters because easy-to-use filtering methods that are free of carbon contaminants do not exist. The goal of this work was to develop a new column based filter to autonomously collect high volume samples of biomass from oligotrophic waters for CSRA using material that can be baked at 450°C to remove potential organic contaminants. A series of filter materials were tested, including uncoated sand, ferrihydrite-coated sand, goethite-coated sand, aluminum-coated sand, uncoated glass wool, ferrihydrite-coated glass wool, and aluminum-coated glass wool, in the lab with 0.1 and 1.0μm microspheres and Escherichia coli. Results indicated that aluminum-coated glass wool was the most efficient filter and that the retention capacity of the filter far exceeded the biomass requirements for CSRA. Results from laboratory tests indicate that for oligotrophic waters with 1×105 cells ml−1, 117l of water would need to be filtered to collect 100μg of PLFA for bulk PLFA analysis and 2000l for analysis of individual PLFAs. For field sampling, filtration tests on South African mine water indicated that after filtering 5955l, 450μg of total PLFAs were present, ample biomass for radiocarbon analysis. In summary, we have developed a filter that is easy to use and deploy for collection of biomass for CSRA including total and individual PLFAs. ► We developed a carbon free filter for radiocarbon analysis of cellular biomass. ► Made from Aluminum coated glass wool. ► The filter can run autonomously to collect large samples from oligotrophic waters. ► Utilized to collect samples from 1.3km depth in a S. African goldmine. ► This filter should greatly expand the collection of PLFAs for radiocarbon analysis.