Characterization of photosynthetic glycogen and alpha-glucosidase from thermophilic cyanobacteria, Lyngbya-Phormidium-Plectonema group B

We harvested filamentous cyanobacteria from an alkaline hot spring (45-50 degree C, pH 8.5-9.0) in Kagoshima Prefecture, and identified it as Lyngbya-Phormidium-Plectonema (LPP) group B by morphological characteristics. From the TCA-soluble fraction of the LPP group B, we isolated glycogen with average chain length of 11 glucose units. The glycogen showed a similar iodine absorption spectrum to that of rabbit liver glycogen. We also recognized the presence of the TCA-insoluble glycogen at about 48% of total glycogen, most of which was bound non-covalently to protein and showed similar iodine absorption spectrum to that of the TCA-soluble glycogen. We also found thermophilic and thermostable alpha -glucosidase with optimum pH 6.5 in this cyanobacteria.