title: Comparative characterization of three bacterial exo-type alginate lyases.
abstract: Alginate, a major acidic polysaccharide in brown macroalgae, has attracted attention as a carbon source for production of ethanol and other chemical compounds. Alginate is monomerized by exo-type alginate lyase into an unsaturated uronate; thus, this enzyme is critical for the saccharification and utilization of alginate. Although several exo-type alginate lyases have been characterized independently, their activities were not assayed under the same conditions or using the same unit definition, making it difficult to compare enzymatic properties or to select the most suitable enzyme for saccharification of alginate. In this study, we characterized the three bacterial exo-type alginate lyases under the same conditions: A1-IV of Sphingomonas sp. strain A1, Atu3025 of Agrobacterium tumefaciens, and Alg17c of Saccharophagus degradans. A1-IV had the highest specific activity as well as the highest productivity of uronate, whereas Alg17c had the lowest activity and productivity. Only dialyzed Atu3025 and Alg17c were tolerant to freezing. Alg17c exhibited a remarkable halotolerance, which may be advantageous for monomerization of alginate from marine brown algae. Thus, each enzyme exhibited particular desirable and undesirable properties. Our results should facilitate further utilization of the promising polysaccharide alginate.
authors.affiliation: Laboratory of Basic and Applied Molecular Biotechnology, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Hirayama
authors.affiliation: Laboratory of Basic and Applied Molecular Biotechnology, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011, Japan.
authors.forename: Wataru
authors.initials: W
authors.lastname: Hashimoto
authors.affiliation: Faculty of Science and Engineering, Department of Life Science, Setsunan University, Neyagawa, Osaka, Japan.
authors.forename: Kousaku
authors.initials: K
authors.lastname: Murata
authors.affiliation: Laboratory of Basic and Applied Molecular Biotechnology, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011, Japan. Electronic address: kawais@kais.kyoto-u.ac.jp.
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Kawai
mesh_terms: D001419:Bacteria / Q000201:enzymology*; D004795:Enzyme Stability; D011133:Polysaccharide-Lyases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D011133:Polysaccharide-Lyases; C016158:poly(beta-D-mannuronate) lyase
keywords: Alginate; Exo-type alginate lyase; Uronate