Jai-Yul Kong

Exopolysaccharides produced by Z. ramigera mutants and analysis of structural change by solution properties

SummaryThe exopolysaccharides produced by Z. ramigera mutants were purified by the precipitation with isopropyl alcohol and characterized. The physiological changes of mutant cells resulted the changes in the structure of the product, Zooglan, which could be determined by the measurement of hydrodynamic properties.Zooglans produced by Z. ramigera SL, SLR and MM1 gave intrinsic viscosities of 14.3 dl/g, 12.2 dl/g and 9.1 dl/g, respectively. The intrinsic viscosity of Zooglan produced by Z. ramigera MM1/pLEX2F increased to 14.8 dl/g. The hydrodynamic property expressed as the intrinsic viscosity of Zooglans could explain the alteration of the structure of Zooglan synthesized by the physiological activities of the mutant cells.

Screening and Identification of Alkaline Protease Inhibitor-Producing Marine-derived Actinomyces.

In this study, we screened and identified the bacterial strain showing high alkaline pretense inhibitor activity from marine environment. Nine bacterial strains with alkaline pretense inhibitor activity were isolated from marine sediments. Among them, strain C12 had the highest alkaline pretense inhibitor activity and was selected for further taxonomical study. On the basis of morphological and physiological characteristics, strain C12 was identified as the genus Streptomyces. A phylogenetic analysis of the 165 rDNA showed that the isolated strain was actually a member of the genus Streptomyces, because the determined sequence exhibited a higher homology with Streptomyces thermocarboxydus. Morphological characteristics showed cylindrical spore chain and smooth spore surface by scanning electron microscope. Strain C12 was grown on all media except for ISP 9 agar. This strain could be grown in the medium containing up to 9% NaCl.