Esculin gel diffusion assay (EGDA): A simple and sensitive method for screening β-glucosidases

β-Glucosidase is an important component of the cellulose degrading enzyme system. The enzyme has other biological applications as well. Often a large number of samples have to be screened for β-glucosidase activity, such as fractions obtained from column chromatography or environmental samples. A gel diffusion technique is presented for screening any number of samples with less labour and cost as compared to other screening methods used. The technique is based on the well-established reaction of β-glucosidase with esculin. Chromatographic fractions were successfully screened to the same degree of accuracy as one of the most commonly used p-nitrophenyl-β-d-glucopyranoside assay.