Extraction of Extracellular Polymers from Natural Biofilms

Abstract:

Using the content of protein and polysaccharide and the content of nucleic acid separately as indicators of total extracellular polymeric substances（EPS） and cell autolysis，five different extraction methods，including thermal，EDTA，NaOH+NaCl，ultrasonic+CER and high speed centrifugation（control） treatments，for EPS from natural biofilms were studied. Results showed that NaOH+NaCl treatment was the most effective for EPS extraction with less nucleic acid contamination. The optimal extraction conditions were 2 mol/L NaOH，0.85% NaCl，extraction time 2.5 h and centrifugal force 7 000 g. With these parameters，the extraction content of EPS was 157.57 mg/L.