Development of a 96-well enzyme-linked solid-phase assay for beta-glucanase and xylanase.

An enzyme-linked sorbent assay (ELSA) for estimating beta-glucanase activity was developed on the basis of the use of biotinylated beta-glucan as a solid-phase substrate. The assay involves the coating of titer plate wells with biotinylated beta-glucan, the partial hydrolysis of this substrate with beta-glucanase, the reaction of the biotin from the unhydrolyzed substrate with an alkaline phosphatase-streptavidin complex, and quantitation of the remaining beta-glucan using alkaline phosphatase. The activity of the bound indicator enzyme, alkaline phosphatase, is proportionally related to the beta-glucanase activity in the sample. The ELSA is simple, can be readily adapted to the routine assay of a large number of samples (as many as 200 per person/day), and has good precision (CV = 4.0-6.4%) and high sensitivity (detects as low as 0. 001 mU of beta-glucanase/assay). A similar assay was developed for xylanase using biotinylated arabinoxylan. The ELSA provides a simple and sensitive estimate of beta-glucanase and xylanase activity.