Stripping interfering sugars from samples using adapted bacteria.
Bacteria adapted to individual sugars quickly remove targeted sugars--stripping them--from samples in which unwanted sugars interfere. Adapted bacteria are equivalent to specific reagents for removal of sugars down to bacterial Km values, micromolar to submicromolar concentrations. Bacterial stripping is a simple method, useful when background sugars in micro-to millimolar concentrations (or larger) interfere with analysis of sought-for sugars. Bacteria such as Escherichia coli and Klebsiella are easily adapted to individual sugars such as lactose, fructose, etc., by growing the bacteria on them. Hence one can easily create (and store) many kinds of cells ready to sponge up or strip out unwanted compounds. E. coli specifically remove several sugars from samples containing 100-500 nmol of sugars, using 1-5 mg of adapted cells, and 25 degrees C temperatures. Stripping requires 1-5 min and consists of mixing cells and sample, spinning down the cells, and withdrawal of stripped supernate. A 1-5 min interval is adequate for uptake and stripping, but far too short for cells to metabolize the sugars that were taken up. Hence the cells do not leak metabolites, but act as specific adsorbants without injection of appreciable byproducts into the sample.