Production of a high-conversion hydrogen production system using hyperthermophiles

• Project/Area Number: 19H02871
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 38020:Applied microbiology-related
• Research Institution: Toyama Prefectural University (2021-2022); Kyoto University (2019-2020)
• Principal Investigator: Kanai Tamotsu 富山県立大学, 工学部, 教授 (10346083)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Project Status: Completed (Fiscal Year 2022)
• Budget Amount: ¥17,290,000 (Direct Cost: ¥13,300,000、Indirect Cost: ¥3,990,000); Fiscal Year 2022: ¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000); Fiscal Year 2021: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000); Fiscal Year 2020: ¥6,760,000 (Direct Cost: ¥5,200,000、Indirect Cost: ¥1,560,000); Fiscal Year 2019: ¥5,330,000 (Direct Cost: ¥4,100,000、Indirect Cost: ¥1,230,000)
• Keywords: キチン / アーキア / 超好熱菌 / 水素 / 水素生産

Outline of Research at the Start

キチンは、地球上でセルロースに次ぐ生産量を誇るバイオマスであるにもかかわらず、その有用性は十分には認知されていない。本研究では、海洋性超好熱性アーキアThermococcus kodakarensis とThermococcus chitonophagus が示す強力なキチン分解・資化システムの分子レベルでの理解を進めると共に、その知見に基づいた高いキチン依存的水素生産能を示す超好熱菌株の育種を目指す。

Outline of Final Research Achievements

The cytosolic hydrogenase gene disruption strain prepared from the Thermococcus kodakarensis KC04ΔtM1 strain showed a significant increase in H2 production as well as in the ratio of H2 production to the amount of chitin consumed. On the other hand, construction of the genetic system in Pyrococcus chitonophagus enabled the author to obtain a gene-disrupted mutant that lacks each three chitinase gene. As a result, ChiA was identified to be the most important enzyme for chitinolysis. Moreover, a new chitinolytic pathway consisting of GlcNAc kinase and GlcNAc-6 phosphate deacetylase was identified in P. chitonophagus.

Academic Significance and Societal Importance of the Research Achievements

超好熱菌Thermococcus kodakarensisを用いた水素生産システムにおいて水素変換効率を向上させた株を取得できたことは、化石燃料に依存しない新たな水素生産系の実用化に向けた大きな成果といえる。さらにはPyrococcus chitonophagusのキチン資化経路の解析により、新規な経路の存在が予想されたことから、広範囲な基質の利用が可能なシステムの構築に繋がることが予想される。