title: Aqueous size-exclusion chromatographic method for the quantification of cyanobacterial native glycogen.
abstract: Cyanobacterial glycogen has gained interest as a valuable biomass feedstock for biofuel production. However, an ideal method for native glycogen quantification has not been developed. Here, we have proposed a simple methodology that enables the quantitative determination of cyanobacterial glycogen concentration with high repeatability using aqueous size-exclusion chromatography with a differential refractive index detector (SEC/RID). Our SEC/RID system also allows size distributions for native glycogen based on hydrodynamic volumes (Vh), which is proportional to the product of the molecular mass (M) and intrinsic viscosity [η], obtained by universal calibration using linear homopolymers of known M with Mark-Houwink-Sakurada parameters. The universal calibration curve achieved a broad linear range (Vh parameter [η]M=2×10(2)-8×10(8)mLg(-1)) with a high correlation coefficient (R(2)=0.9942), because the developed system is equipped with an OHpak SB-806M HQ aqueous column containing four types of polyhydroxy methacrylate-based particles with different particle and pore sizes. Based on the SEC/RID system, response of molecular size distribution of glycogen in microalgae to the cultivation condition was first observed. Our established SEC/RID method has several advantages over conventional techniques, including the simultaneous quantitative and size distribution analyses of glycogen, and represents a potentially useful tool to elucidate the relationship between structural properties and the roles of glycogen in metabolism.
authors.affiliation: Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodaicho, Nadaku, Kobe 657-8501, Japan. izumi_yoshihiro@port.kobe-u.ac.jp
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Izumi
authors.forename: Shimpei
authors.initials: S
authors.lastname: Aikawa
authors.forename: Fumio
authors.initials: F
authors.lastname: Matsuda
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Hasunuma
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kondo
mesh_terms: D002850:Chromatography, Gel / Q000379:methods*; D000458:Cyanobacteria / Q000737:chemistry / Q000378:metabolism*; D006003:Glycogen / Q000032:analysis* / Q000378:metabolism; D057446:Hydrodynamics; D058086:Microalgae; D008970:Molecular Weight; D011102:Polyhydroxyethyl Methacrylate / Q000737:chemistry; D015203:Reproducibility of Results; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D014867:Water; D011102:Polyhydroxyethyl Methacrylate; D006003:Glycogen