Physiological properties and genetic analysis related to exopolysaccharide (EPS) production in the fresh-water unicellular cyanobacterium Aphanothece sacrum (Suizenji Nori)

The Journal of General and Applied Microbiology

Kaori Ohki¹  Yu Kanesaki²  Noriyuki Suzuki³ 

[1] Department of Marine Bioscience, Fukui Prefectural University;NODAI Genom Research Center, Tokyo University of Agriculture;School of Materials Science, Japan Advanced Institute of Science and Technology

关键词: Aphanothece sacrum;    Exopolysaccharide (EPS);    unicellular cyanobacterium;    Wzy-dependent pathway;   

DOI  :  10.2323/jgam.2018.04.004

学科分类：微生物学和免疫学

来源: Applied Microbiology, Molecular and Cellulrar Biosciences Research Foundation

【 摘 要 】

The clonal strains, phycoerythrin(PE)-rich- and PE-poor strains, of the unicellular, fresh water cyanobacterium Aphanothece sacrum (Suringar) Okada (Suizenji Nori, in Japanese) were isolated from traditional open-air aquafarms in Japan. A. sacrum appeared to be oligotrophic on the basis of its growth characteristics. The optimum temperature for growth was around 20°C. Maximum growth and biomass increase at 20°C was obtained under light intensities between 40 to 80 μmol m–2 s–1 (fluorescent lamps, 12 h light/12 h dark cycles) and between 40 to 120 μmol m–2 s–1 for PE-rich and PE-poor strains, respectively, of A. sacrum . Purified exopolysaccharide (EPS) of A. sacrum has a molecular weight of ca. 104 kDa with five major monosaccharides (glucose, xylose, rhamnose, galactose and mannose; ≥85 mol%). We also deciphered the whole genome sequence of the two strains of A. sacrum. The putative genes involved in the polymerization, chain length control, and export of EPS would contribute to understand the biosynthetic process of their extremely high molecular weight EPS. The putative genes encoding Wzx-Wzy-Wzz- and Wza-Wzb-Wzc were conserved in the A. sacrum strains FPU1 and FPU3. This result suggests that the Wzy-dependent pathway participates in the EPS production of A. sacrum.

【 授权许可】

Unknown