Leuconostoc mesenteroides LM34 was isolatedfrom kimchi, a traditional fermented Korean food. L. mesenteroides LM34 produced extracellular glucansucrase(DSRLM34), which is responsible for the synthesis ofsoluble glucan using sucrose. The DSRLM34 gene consistsof a 4,503 bp open reading frame (ORF) and encodes anenzyme of 1,500 amino acids with an apparent molecularmass of 165 kDa. The deduced amino-acid sequenceshowed the highest amino-acid sequence identity (98%) tothat of glucansucrase of Lactobacillus lactis. The gene wasover-expressed in Escherichia coli strain and the recombinantenzyme (rDSRLM34) was purified. Both DSRLM34 andrDSRLM34 synthesized glucan mainly containing α-1, 6glucosidic linkage and branched α-1, 3 glucosidic linkages. The enzyme exhibited optimum activity at 30oC andpH 5.0. DSRLM34 has promising potential as a thickeningagent in sucrose-supplemented milk.