Simple ELISA using Polyclonal Antibody and Lectin for Determination of Soluble Chitosan - Like Polysaccharide in Bacterial Culture

We have developed a simple enzyme-linked immunosorbent assay (ELISA) for the direct determination of chitosan-like polysaccharide (CP) produced in the cultures of Citrobacter strains. CP in sample solutions was reacted with anti-CP rabbit polyclonal antibody immobilized in a 96-well microtiter plate and sandwiched with horseradish peroxidase-conjugated lectin, followed by color development by the enzyme activities. Using standard chitosan solutions, a good standard curve (R2=0.977) was established between 0 and 250 μg l-1 with the average coefficient of variation of 7.0%, and CP in the diluted culture supernatants could be directly determined. This method can apply for the direct determination of other polysaccharides in solution by selecting an inexpensive custom-made polyclonal antibody and an appropriate lectin, both of which may be commercially available.