Glucuronic acid is a common chemical moiety that decorates the xylan polymer of hemicellulose. This chemical substituent impairs both enzymatic and acidic hydrolysis of xylosidic bonds. The alpha-glucuronidase enzyme hydrolyzes the 1,2-linked glucuronic acid from the terminal, non-reducing xylose of xylo-oligosaccharides. There are relatively few alpha-glucuronidase genes in the public databases. We have developed an assay with commercially available reagents that can be used to search DNA libraries for alpha-glucuronidase genes in a high-throughput, solid phase activity screen.