Paenibacillus sp. S29 was isolated from soil and produces an alginate lyase. The molecular weight of this enzyme was 32 kDa and the N-terminal amino acid sequence was ASVTKST. The optimal pH was approximately 8.7 and the enzyme was stable over a pH range of 5.6 to 8.8 at 40 A degrees C for 60 min. The optimal temperature was approximately 50 A degrees C, and the residual activity was not decreased at temperatures of up to 40 A degrees C at pH 8 for 30 min. Paenibacillus sp. S29 alginate lyase had also a little activity toward hyaluronic acid. Poly G and poly M separated from alginate were degraded efficiently, and poly M was the more susceptible substrate. The maximum amount of reducing sugar released by the enzyme was 261 mg per gram of sodium alginate. The main sugar released was monosaccharide (unsaturated uronate) and small amounts of oligosaccharides of degree of polymerization 2-6 were also released.