title: Purification and characterization of alginate lyase from streptomyces species strain A5 isolated from banana rhizosphere.
abstract: To characterize the alginate lyase produced by rhizosphere Streptomyces, Streptomyces sp. A5 was isolated from banana rhizosphere, and its extracellular lyase was purified to an electrophoretically homogeneous state. The lyase has a molecular mass of 32 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The optimum temperature and pH were 37 degrees C and pH 7.5, respectively. Ninety-two percent of the activity was lost after incubation at 70 degrees C and pH 7.5 for 20 min. The enzyme was inhibited by 0.05 M SDS and 2 mM Hg2+, Cu2+, and Fe3+, but EDTA enhanced the enzyme activity. The Km value of the lyase was 0.13 mg mL-1 with the substrate sodium alginate. The lyase had substrate specificity for polyguluronate units in the alginate molecules. The alginate oligomers prepared by the lyase show growth-promoting activity on the roots of banana plantlets. These results indicated that the encapsulation method using alginate microbeads to inoculate beneficial streptomycete strains might be beneficial to the root growth of banana plantlets.
authors.affiliation: State Key Laboratory for Biocontrol and Department of Biochemistry, School of Life Sciences, Zhongshan Sun Yatsen University, Guangzhou 510275, People's Republic of China.
authors.forename: Lixiang
authors.initials: L
authors.lastname: Cao
authors.forename: Lujing
authors.initials: L
authors.lastname: Xie
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Xue
authors.forename: Hongming
authors.initials: H
authors.lastname: Tan
authors.forename: Yuhuan
authors.initials: Y
authors.lastname: Liu
authors.forename: Shining
authors.initials: S
authors.lastname: Zhou
mesh_terms: D004791:Enzyme Inhibitors / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D028521:Musa / Q000382:microbiology*; D011133:Polysaccharide-Lyases / Q000037:antagonists & inhibitors / Q000302:isolation & purification* / Q000378:metabolism*; D027343:Rhizome / Q000382:microbiology*; D013302:Streptomyces / Q000201:enzymology* / Q000302:isolation & purification; D013379:Substrate Specificity
chemical_list: D004791:Enzyme Inhibitors; D011133:Polysaccharide-Lyases; C016158:poly(beta-D-mannuronate) lyase