Molelcular mechanisms of exopolysaccharide production in edible cyanobacterium, Aphanothece sacrum (Suizenji-Nori)

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K07557
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Aquatic bioproduction science
• Research Institution: Fukui Prefectural University
• Principal Investigator: OHKI Kaori 福井県立大学, 海洋生物資源学部, 名誉教授 (90101104)
• Co-Investigator(Kenkyū-buntansha): 兼崎 友 静岡大学, グリーン科学技術研究所, 特任助教 (70380293)
• Co-Investigator(Renkei-kenkyūsha): YOSHIKAWA Sinya 福井県立大学, 海洋生物資源学部, 准教授 (20405070)
• Research Collaborator: KANEKO Tatsuo 北陸先端技術大学院大学, 環境エネルギー領域, 教授 ; TAKAGI Keiichi 若狭湾エネルギー研究センター, 生物資源研究室, 室長
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: スイゼンジノリ / Aphanothece sacrum / 単細胞ラン藻 / 細胞外多糖合成 / 細胞外多糖合成関連遺伝子 / 全ゲノム解析 / exopolysaccharide (EPS)

Outline of Final Research Achievements

Unicellular cyanobacterium Aphanothece sacrum (Suizenji-Nori) has been cultured in open-air aqua-farms for more than 300 years as a food source in Japan. At present, the exopolysaccharide (EPS) of A. sacrum attracts as a useful bio-resource. To elucidate the molecular mechanisms related to EPS synthesis and export in A. sacrum, two clonal strains were isolated from a traditional aqua-farm and used. Results revealed that (1) the optimum conditions for growth and EPS synthesis were at around 20C and the light intensity of ca. 80 μmole/sq.m・sec (12h light/12h dark cycles) , (2)purified EPS consisted of five major monosaccharids with a large molecular weight of ca. 10,000 kDa. (3)creation of mutants related to EPS synthesis was tried using heavy ion carbon beam irradiation. (4) the whole genome sequence of the two strains were determined. Analysis of putative genes involved in EPS synthesis and export suggests that the Wzy-dependent pathway is participate in EPS production of A. sacrum.

Free Research Field

植物生理学・藻類学