Growth on a wheat bran media induced production of an extracellular beta-glucanase by Rhizomucor miehei (DSM 1330). The enzyme was purified to homogeneity. Substrate specificity studies coupled with protein database similarity searching using mass spectrometry-derived sequence data indicate it to be an endo-1,3(4)-beta-glucanase (EC 188.8.131.52). The enzyme was characterised in terms of potential suitability for use in animal (poultry) feed. Significant activity was observed over the entire pH range typical of the avian upper digestive tract (pH 2.6-6.5). The enzyme was also found to be more thermostable than current commercialized beta-glucanases, particularly when heated at a high enzyme concentration, and retained twice as much residual activity as the latter upon exposure to simulated avian digestive tract conditions. There are no previous reports of the production, purification or characterization of a beta-glucanase from a Rhizomucor, and the enzyme's application-relevant physicochemical characteristics render it potentially suited for use in animal feed.