PRODUCTION OF LEVANBIOSE BY A LEVAN-DEGRADING ENZYME FROM STREPTOMYCES-EXFOLIATUS F3-2

Levan-assimilating microorganisms obtained from soil samples were scre ened for levan-degrading enzyme production. Among them, the strain F3- 2 was found to produce an extracellular levan-degrading enzyme that hy drolyzed levan to a disaccharide identified as levanbiose. The strain F3-2 was identified as Streptomyces exfoliatus F3-2. This levan-degrad ing enzyme was specifically induced by levan, and the activity was inc reased to 2.58 units/ml by improvement of the culture conditions. The optimum temperature and pH for the enzyme reaction were 60-degrees-C a nd 5.5, respectively. The crude levan-degrading enzyme was stable with in a pH range of 3.0 to 9.0 and at up to 50-degrees-C. Using this crud e levan-degrading enzyme, 50 mg/ml of levan was converted to levanbios e in amounts of 42 mg/ml.