[H-CG34] [JJ] Systems of life in closed bio-ecosystems and planets

[HCG34-03] Growth and tolerance of a terrestrial cyanobacterium, Nostoc sp. HK-01 under harsh environment

*Shunta Kimura¹, Kotomi Inoue¹, Sosaku Ichikawa¹, Kaori Tomita-Yokotani¹ (1.Graduate School of Life and Environmental Sciences, University of Tsukuba)

Keywords:Closed bio-ecosystems, Cyanobacteria, Dry heat tolerance, Martian regolith simulant, Nostoc sp. HK-01

A terrestrial cyanobacterium, Nostoc sp. HK-01, has several abilities; photosynthesis, nitrogen fixation, utility as food, and tolerance to extraterrestrial environments. Nostoc sp. HK-01 may be utilized for biochemical circulation in closed bio-ecosystems, such as Mars. Tolerance to extraterrestrial environments are important for transportation to Mars. Akinetes, which are dormant cells of Nostoc sp. HK-01, are tolerant against dry heat, upto 100 ^oC for 10h. These results indicate that some functional substances which provide tolerance against heat exist in the akinete cells. Akinetes of Nostoc sp. HK-01 could be transported to Mars. Before we introduce Nostoc sp. HK-01 to Mars’ environments, we need to understand its growth in an environment with poor nutrition. We tested whether akinetes of HK-01 can grow using components of their dead cells or/and Martian regolith simulant. We will discuss the possibility that a colony of HK-01 can be grown in an environment with poor nutrition. Nostoc sp. HK-01 could contribute to soil formation from Martian regolith, so that plants could grow. Nostoc sp. HK-01 is a good candidate for an initial organism to introduce into the Martian environment.