Polysaccharide concentration
The Phenol-sulfuric acid method, a widely used quantitative assay for
glucose estimation was used to estimate the polysaccharide concentration
present in a biofilm [72]. Briefly, 150 µl of extractant was added
to 450 µl of concentrated sulfuric acid and 90µl of 5% phenol in a 13
mm glass tube. The tube was gently swirled to mix, incubated in a 90 °C
water bath for 10 mins and cooled to RT. Two hundred microliters was
pipetted in triplicates into a 96-well plate and absorbance measured at
OD490nm. Varying concentrations of glucose
(2/1.75/1.5/1/0.5/0 mg/ml) were used for the control and standard curve.