An endospore-forming bacterial strain that was isolated from the hot extract of su,oar beet and identified as a strain of Bacillus licheniformis excretes an active 38-kDa exopolygalacturonate lyase. The enzyme was purified to homogeneity by ammonium sulfate precipitation, gel filtration, hydrophobic interaction chromatography, and ion-exchange chromatography. The pH optimum of the enzyme was found to be 11.0 and the temperature optimum, 69 degrees C. Its activity is dependent on Ca2+; 100% activity was retained at 65 degrees C after 2 h. The N-terminal sequence was determined and found to contain the motif GFAALNGGTTGG in accordance with the motif G(aro)a(S-7x)TxGG in other pectate lyases of the pelADE and pelBC families. 4,5-Unsaturated trigalacturonate was released as the product by the action of the enzyme.