title: Depolymerization of alginate into a monomeric sugar acid using Alg17C, an exo-oligoalginate lyase cloned from Saccharophagus degradans 2-40.
abstract: Macroalgae are considered to be promising biomass for fuels and chemicals production. To utilize brown macroalgae as biomass, the degradation of alginate, which is the main carbohydrate of brown macroalgae, into monomeric units is a critical prerequisite step. Saccharophagus degradans 2-40 is capable of degrading more than ten different polysaccharides including alginate, and its genome sequence demonstrated that this bacterium contains several putative alginate lyase genes including alg17C. The gene for Alg17C, which is classified into the PL-17 family, was cloned and overexpressed in Escherichia coli. The recombinant Alg17C was found to preferentially act on oligoalginates with degrees of polymerization higher than 2 to produce the alginate monomer, 4-deoxy-L: -erythro-5-hexoseulose uronic acid. The optimal pH and temperature for Alg17C were found to be 6 and 40 °C, respectively. The K                         (M) and V                         (max) of Alg17C were 35.2 mg/ml and 41.7 U/mg, respectively. Based on the results of this study, Alg17C could be used as the key enzyme to produce alginate monomers in the process of utilizing alginate for biofuels and chemicals production.
authors.affiliation: School of Life Sciences and Biotechnology, Korea University, Seoul, 136-713, South Korea.
authors.forename: Hee Taek
authors.initials: HT
authors.lastname: Kim
authors.forename: Jae Hyuk
authors.initials: JH
authors.lastname: Chung
authors.forename: Damao
authors.initials: D
authors.lastname: Wang
authors.forename: Jieun
authors.initials: J
authors.lastname: Lee
authors.forename: Hee Chul
authors.initials: HC
authors.lastname: Woo
authors.forename: In-Geol
authors.initials: IG
authors.lastname: Choi
authors.forename: Kyoung Heon
authors.initials: KH
authors.lastname: Kim
mesh_terms: D000464:Alginates / Q000378:metabolism*; D034241:Alteromonadaceae / Q000201:enzymology* / Q000235:genetics; D003001:Cloning, Molecular; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D011133:Polysaccharide-Lyases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D013379:Substrate Specificity; D013400:Sugar Acids / Q000378:metabolism*; D013696:Temperature
chemical_list: D000464:Alginates; D011994:Recombinant Proteins; D013400:Sugar Acids; D011133:Polysaccharide-Lyases; C016158:poly(beta-D-mannuronate) lyase