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.